What Works in Youth Suicide Prevention? A Systematic Review and Meta-Analysis

Authors: Jo Robinson, Eleanor Bailey, Katrina Witt, Nina Stefanac, Allison Milner, Dianne Currier, Jane Pirkis, Patrick Condron, Sarah Hetrick

Abstract

Background

Young people require specific attention when it comes to suicide prevention, however efforts need to be based on robust evidence.

Methods

We conducted a systematic review and meta-analysis of all studies examining the impact of interventions that were specifically designed to reduce suicide-related behavior in young people.

Findings

Ninety-nine studies were identified, of which 52 were conducted in clinical settings, 31 in educational or workplace settings, and 15 in community settings. Around half were randomized controlled trials. Large scale interventions delivered in both clinical and educational settings appear to reduce self-harm and suicidal ideation post-intervention, and to a lesser extent at follow-up. In community settings, multi-faceted, place-based approaches seem to have an impact. Study quality was limited.

Interpretation

Overall whilst the number and range of studies is encouraging, gaps exist. Few studies were conducted in low-middle income countries or with demographic populations known to be at increased risk. Similarly, there was a lack of studies conducted in primary care, universities and workplaces. However, we identified that specific youth suicide-prevention interventions can reduce self-harm and suicidal ideation; these types of intervention need testing in high-quality studies.

Research in ContextEvidence Before This StudyPrior to this study systematic reviews in suicide prevention have been limited by either only including RCTs, or by concentrating on particular settings (e.g., schools) or intervention type (e.g., gatekeeper training), and as such do not cover the full spectrum of approaches. The more comprehensive systematic reviews do not focus specifically on youth.Added Value of This StudyThis is the first systematic review and meta-analysis to synthesize the full spectrum of suicide prevention approaches in young people. It identified a large number of studies conducted across clinical, educational/workplace and community settings. Studies also tested the full spectrum of interventions including universal means restriction and educational interventions, selective interventions such as training programs, indicated interventions such as cognitive or dialectical behavior therapy, and multimodal interventions that combined education with either screening or gatekeeper training. The meta-analysis found that interventions delivered in both clinical and educational settings appear to have an impact on suicide-related outcomes at post-intervention and follow-up. In community settings, multi-faceted, place-based approaches seem to have an impact on rates of suicide and self-harm. Overall, study quality was limited.Implications of All the Available EvidenceThe review identified that specific youth suicide-prevention interventions can reduce both self-harm and suicidal ideation in clinical, school and community settings, challenging the nihilism that often pervades in suicide prevention. Indeed, the number and range of studies identified by this review is encouraging and reflects increasing investment and best practice internationally when it comes to youth suicide prevention. However, there was an absence of studies conducted in low-middle income countries where large numbers of suicides occur, or with specific populations known to be at elevated risk of suicide, such as indigenous or same-sex attracted young people. Similarly, few studies were conducted in primary care, workplace or university settings, and very few utilized digital platforms. Additionally, many studies simply tested interventions that had previously been designed for adults as opposed to young people specifically. Together these findings suggest that important opportunities for youth suicide prevention are currently being missed. These gaps now need to be addressed by researchers, research funders, and by policy makers if we are to successfully address the rising rates of suicide among young people worldwide.Alt-text: Unlabelled Box

Introduction

Suicide is the second-leading cause of death among young people and rates appear to be increasing [1]. Suicidal thoughts and behaviors (defined as suicide attempt or self-harm with clear or unclear suicidal intent) are more common than suicide [2] and predict future suicide and suicide attempts [3], with the period following a first suicide attempt associated with highest risk [4]. Presenting to hospital with self-harm significantly predicts subsequent suicide in youth [5]; with the period immediately following discharge from psychiatric inpatient treatment associated with highest risk for suicide [6]. The period following hospital discharge therefore provides a crucial opportunity for intervention. Suicidal ideation is a necessary precursor to suicide attempt and as such also requires intervention. Although suicidal ideation is arguably a distinct concept from suicidal behavior, for ease of reading it is included under the term “suicide-related behavior” throughout this review unless otherwise specified.

The majority of OECD countries have a national suicide prevention strategy and many identify young people as requiring specific attention [7], [8], [9]. In accordance with international best practice, most strategies recommend a comprehensive approach to suicide prevention spanning universal approaches (i.e., delivered to the whole population), selective approaches (i.e., delivered to groups or communities believed to be at higher risk of suicide) and indicated approaches (i.e., delivered to individuals displaying suicide-related behaviors). Strategies also recommend interventions operate across a range of settings, including clinical, educational, workplace and community settings [1]. More recently, strategies have called for interventions to be delivered in digital, as well as face-to-face, settings [10], [11].

Strategies must encompass evidence-based interventions if they are to reduce suicide [1]. Generating such evidence in suicide prevention, however, is complex [12]. Statistically, suicide is a relatively rare event, therefore it is often unfeasible to obtain sample sizes necessary to demonstrate the impact of interventions on this outcome. Moreover, many interventions do not lend themselves to being tested using randomized controlled trials (RCTs), typically considered the gold-standard [13]. As such, researchers assess changes in other more prevalent outcomes, including self-harm and suicidal ideation, using alternative study designs. Therefore, when synthesizing the evidence regarding what works in youth suicide prevention, alternative study designs warrant consideration.

Whilst previous reviews have synthesized this evidence, many only include RCTs [14]. Additionally, many concentrate on particular settings (e.g., schools) [15], or types of intervention (e.g., gatekeeper training programs) [16], and as such do not cover the full spectrum of approaches. Finally, systematic reviews that include a range of study designs and intervention types do not focus specifically on youth [17], [18]. Hence, a comprehensive review of the literature on youth suicide prevention interventions spanning the range of settings, study designs and intervention types, is required to better understand what works in youth suicide prevention. This will help policy makers, clinicians, service providers and commissioners determine the focus of future suicide prevention efforts.

We conducted a systematic review and, where possible, meta-analysis, of all studies examining the impact of interventions that were specifically designed to reduce suicide-related behavior in young people. Overcoming the limitations of previous reviews, we placed no restriction on study setting, intervention approach, or study design.

Methods

The methodology was informed by the Cochrane Collaboration [19] and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [20].

Study Selection and Classification

Inclusion Criteria

Studies of any design were eligible for inclusion in this review, provided [1] evaluated the impact of an intervention specifically designed to reduce suicide-related behavior; [2] assessed a suicide-related outcome, including suicide, suicide attempt, self-harm (defined as intentional self-injury and/or self-poisoning where suicidal intent was either not specified or was unclear), suicidal ideation, suicide risk, and/or reasons for living; [3] targeted young people aged 12–25 and/or if data on young people (mean age between 12·0 and 25·0) was specifically reported; [4] were published in a peer-reviewed journal or identified via the reference lists of included articles; and [5] were written in English.

Exclusion Criteria

Studies were excluded from the review [1] they were not implemented with the expressed and primary purpose of preventing or reducing suicide-related behavior. Under this criterion, studies of indicated interventions were excluded if they did not recruit participants based on present or recent suicidal ideation or behavior. Additionally, studies of means restriction approaches were included only if the intervention was implemented, wholly or partially, to prevent suicide. As such, studies of firearm regulations implemented with the expressed and primary purpose of preventing homicide were excluded under this criterion. Studies were also excluded if [2] did not measure and report on a suicide-related outcome (as defined above); this included studies that exclusively measured non-suicidal self-injury, as this is generally considered to be a separate phenomenon; [3] did not target young people, or if data relating to outcomes for young people could not be disaggregated from that adults; [4] employed a non-experimental design; [5] were not published in a peer-reviewed journal; [6] were not available in English; or [7] did not contain any unique relevant data over and above the first included study.

Search Strategy

We searched Medline, PsycINFO, and EMBASE from January 1 1990 to September 21, 2017. Keywords relevant to suicide-related behavior, intervention type and youth were combined using standard Boolean operators (see Appendix). Key words were developed by consensus among the author group and in consultation with a librarian. In addition, we hand-searched the reference lists of all previous reviews retrieved via the search.

In the first instance study titles and abstracts were screened by five of the review authors (EB, JR, SH, NS, KW). Due to the large number of studies retrieved two review authors independently screened 10% of the total number of records retrieved. Cohen's Kappa [21] was 0·748 and Prevalence-Adjusted and Bias-Adjusted Kappa (PABAK [22]) was 0·978, indicating excellent agreement regarding inclusion and exclusion of studies. Discrepancies were resolved by discussion. In the second stage of screening, full texts of potentially relevant studies were screened for inclusion by four authors (EB, JR, SH, NS). Full text double-screening was not undertaken, but review authors met regularly to resolve any queries.

Data Extraction and Classification

Data were extracted independently by seven authors (JR, EB, SH, NS, KW, DC, AM) using a pilot tested pro forma. The following information was (i) author(s) and publication date; (ii) country; (iii) study design; (iv) setting from which participants were recruited; (v) study sample or population characteristics; (vi) intervention description; (vii) details of control or comparison group (classified as treatment as usual (TAU), enhanced TAU and placebo), and; (viii) outcome data on suicide deaths, suicide attempt, suicidal ideation, suicide-related behavior, and/or self-harm at the point of post-intervention and (where appropriate) longest follow-up (note that follow-up periods varied). Where studies used more than one measure for an outcome, data from the measure that was most commonly used across all included studies were used, as has been done previously [23]. Two authors (SH and KW) undertook double data entry of all outcome data.

Studies were classified according to the following taxonomy. In the first instance studies were classified according to the setting from which the participants were recruited (i.e. clinical, education or workplace, and community). If participants were recruited from multiple settings, the study was classified according to the setting from which participants were primarily recruited. Studies were then classified by study design (i.e. RCTs and non-RCTs) and then by intervention approach (i.e. universal, selective, indicated). Some studies combined a number of different intervention approaches. In these cases studies were classified as ‘multi-modal’ when the intervention comprised a number of different components implemented together (e.g. psycho-education AND screening), and ‘multiple’ when studies tested the impact of different interventions that were implemented separately (e.g. psycho-education program in location A and gatekeeper training in location B). They were then classified according to intervention type (e.g. means restriction, educational, therapeutic). For the therapeutic interventions, the therapeutic modality itself was also specified. For example, within this category there were a number of studies that tested cognitive behavioral therapy (CBT), dialectical behavioral therapy (DBT) and so on.

Study Quality

An assessment of study quality was conducted. For all RCTs, this was assessed based on the Cochrane Collaboration Risk of Bias Tool [19]. In the majority of trials, as is often the case [24], blinding of participants and therapists was not possible. Each trial was therefore assessed with regard to random sequence generation, allocation concealment, ascertainment of self-harm, outcome assessor blinding, whether analyses were conducted according to the intention-to-treat (ITT) principle, and rates of attrition. For the latter criterion, an attrition rate of 15% or less on the primary outcome at the longest follow-up point indicated low risk of bias.

Non-RCTs were assessed in two ways. For those conducted in clinical, educational, or workplace settings (where a range of study designs were employed) we used a set of criteria based on resources from the Cochrane Effective Practice and Organization of Care (EPOC) group [25]. We assessed whether or [1] the study was adequately powered; [2] outcome assessors were blinded to treatment allocation (for studies where outcomes were measured via interview); [3] the attrition rate was below 15%; and [4] the authors used statistical testing to measure change.

Studies in community settings employed either an ecological or interrupted time series design. Here two criteria were used to assess whether or not data were collected at multiple time points before and after the intervention [26], and whether or not the intervention itself was likely to affect data collection. “Multiple time points” was defined as at least twice before or after implementation of the intervention. The intervention was considered not to affect data collection if sources and methods of data collection were the same before and after the intervention, or if data were collected from official sources (e.g. coronial records).

Data Synthesis

Meta-analysis was only conducted for RCTs. We analyzed data separately according to study setting. Because self-harm can encompass suicide attempts, is a key predictor of future suicide [27], and is more prevalent and more commonly assessed than suicide, self-harm (measured dichotomously) was our primary outcome and all dichotomous self-harm and suicide attempt data were combined. Additional outcomes were self-harm measured continuously, suicide and suicidal ideation (measured dichotomously and continuously). Where studies had more than one intervention arm, we included those arms that provided relevant data and split the control group to avoid double counting [28].

For dichotomous data, we pooled data between studies using the relative risk with 95% confidence interval. For continuous outcomes, given the range of different tools used, means and standard deviations were pooled using the standardized mean difference (SMD) using the Hedges' adjusted g with a 95% confidence interval. SMD effect sizes of 0·2 were considered small, 0·5 were considered medium, and ≥ 0·8 were considered large [29]. Measurement scales were standardized so that higher scores were indicative of greater levels of suicidal ideation. For both continuously- and dichotomously-measured outcomes, pooled effect size estimates were calculated using the DerSimonian-Laird random effects model [30] implemented using Comprehensive Meta-Analysis 2·2·064 software [31].

Between-study heterogeneity was measured using the I^2^ statistic. I^2^ values of 25%, 50% and 75% or larger are indicative of small, moderate and high heterogeneity, respectively [32].

Subgroup Analysis

For the primary outcome we undertook three subgroup analyses to investigate whether the intervention approach, intervention type and, for those interventions coded as psychotherapy, the therapeutic modality modified the pooled effect sizes.

First, intervention approach was coded as universal, selective or indicated. Second, type of intervention was categorized as psychotherapy, brief contact, or educational. Psychotherapy interventions were established psychotherapeutic approaches belonging to a particularly theoretical or philosophical school. Brief contact interventions were defined as those interventions that [1] focused on maintaining contact or facilitating re-engagement with services via a minimal amount of supportive contact, including provision of an emergency or crisis card as defined by Milner et al. [33]; or [2] interventions delivered within a very brief period, such as screening and referral or provision of one-off assessment and supportive therapy. Educational interventions delivered psycho-education about suicide-related behaviors, mental illness associated with these behaviors, signs and symptoms to look out for and advice on how to respond. Finally, trials coded as psychotherapy were further categorized by modality as CBT; DBT; mentalisation therapy; problem solving; motivational interviewing; supportive therapy; family therapy; interpersonal psychotherapy; combined (where several modes of psychotherapy were combined); or other (where the intervention did not clearly fit any category of named therapeutic approach).

Sensitivity Analysis

The robustness of results of the meta-analysis was checked for the primary outcome by conducting sensitivity analyses. RCTs judged as high or unclear risk of bias for allocation concealment, and RCTs where more than 15% of participants were lost to follow-up or where no data were reported, were excluded from this analysis.

For studies in which no data amenable to meta-analysis were reported, a narrative synthesis of results was conducted.

Results

Search Results

In total, 34,463 articles were retrieved via database searching and an additional four via the reference lists of included articles. Following initial screening, 572 full-text articles were retrieved, of which 105 met our inclusion criteria. Six were secondary publications that were included as they reported novel data [34], [35], [36], [37], [38], [39]. The review therefore includes findings from 105 articles corresponding to 99 unique studies (see Fig. 1).Fig. 1PRISMA flow diagram.Fig. 1

Overall Description of Included Studies

Half (52·5%) of included studies were conducted in clinical settings (Table 1, Table 2), 31 (31·3%) in educational or workplace settings (Table 3, Table 4), and 16 (16·2%) in community settings (Table 5, Table 6). Most studies tested indicated interventions (k = 66; 66·7%), followed by universal (k = 17; 17·2%), multimodal (k = 11; 11·1%), and selective (k = 2; 2·0%) interventions. Three studies (3·0%) evaluated multiple interventions. Forty-eight studies (48·5%) were RCTs. This included 33 (63·5%) of the studies conducted in clinical settings and 15 (48·4%) of those conducted in educational or workplace settings. None of the community-based studies were RCTs.Table 1Randomized controlled trials conducted in clinical settings (N = 33).Table 1Study; countryTarget populationParticipantsIntervention descriptionComparison conditionRisk of biasSuicide related outcome(s) assessed; longest follow-upAlavi et al. (2013) [41]IranInclusion: Young people admitted to hospital for a SAExclusion: SH w/o intent; no current SI; inability to participate in psychotherapy; diagnosed with bipolar, psychosis, pervasive developmental or substance use disordersRecruited Hospital/EDWhole sampleN = 30Mean 16.1 (SD: 1.4; Range: 12–18Gender: 10% maleTreatment groupN = 15Mean 16.1 (SD: 1.6)Gender: 6.7% maleControl groupN = 15Mean 16.0 (SD: 1.2)Gender: 13.3% maleIndividual cognitive behavioral therapy plus TAULength: 12 sessions over 3 monthsDeveloped Stanley et al. (2009)aDelivered NRTAU: routine psychiatric intervention and follow up; pharmacotherapy if needed.Random sequence generation Alternate allocationAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out Yes (0.0%)Was ITT analysis NRSI (continuous): Beck Scale for Suicidal Ideation (BSSI)Longest follow-up: Post-intervention onlyAsarnow et al. (2011) [65]USAInclusion: Young people who presented to ED with SA or SIExclusion: Acute psychosis or other symptoms that impede consenting and/or assessment processRecruited Hospital/EDWhole sampleN = 181Mean 14.7 (SD: 2.0; Range: 10–18)Gender: 30.9% maleTreatment groupN = 89Mean 14.8 (SD: 2.1)Gender: 33.7% maleControl groupN = 92Mean 14.6 (SD: 1.9)Gender: 28.3% maleBrief contact interventionCompliance enhancement measures mixed with family therapy plus TAULength: 1 monthDeveloped Based on Rotheram-Borus et al. (1996)b and adapted by authorsDelivered MH professionalsEnhanced TAU: usual ED care, with staff education on linking to treatment, reducing access to means, risks of substance use.Random sequence generation Computer generated algorithmAllocation concealment Independent researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out rate for SH at post-intervention: Yes (11.6%)Was ITT analysis YesSI (dichotomous): DISC-IV, an clinician administered diagnostic interviewSA (dichotomous): DISC-IV, an clinician administered diagnostic interview and Harkavy Asnis Scale (HASS)Longest follow-up: Post-intervention onlyAsarnow et al. (2017) [42]USAInclusion: i) Young people who had presented after engaging in SH (SA or NSSI included) within the last three months; ii). history of repetitive SH (≥ 3 lifetime episodes)Exclusion: symptoms interfering with participation in assessments or intervention (psychosis, substance use) and inability to speak EnglishRecruited Hospital/ED and MH outpatientWhole sampleN = 42Mean 14.62 (SD: 1.83)Gender: 11.9% maleTreatment groupN = 20Mean 14.35 (SD: 1.81)Gender: 10.0% maleControl groupN = 22Mean 14.86 (SD: 1.86)Gender: 13.6% maleSAFETY programCombined intervention consisting of CBT and DBT informed family intervention that included formulation driven CBT, DBT and family centered interventions. Each family had two one for the young person and one for the parents and there were joint family sessions as well as separated sessions.Length: 12 sessions over 3 monthsDeveloped study authorsDelivered MH professionalsEnhanced TAU: in-clinic parent education on risk of repetition, accessing treatment; 3 + phone-calls monitoring safety, encouraging treatment attendance.Random sequence generation Computerized randomization programAllocation concealment Enrolment and assessment staff masked to randomization statusAscertainment of DSH Self-reportOutcome assessor YesLess than 15% drop-out No (23.8% for self-reported outcomes)Was ITT analysis YesSA (dichotomous): used a slight modification of the clinician administered Columbia Suicide Severity Rating Scale (C-SSRS)Longest follow-up: 12 months post-baselineBertolote et al. (2010) [66]; Fleischmann et al. (2008) [34]Multi-nationalInclusion: Young people who presented to ED following SH/self-poisoningExclusion: ‘any clinical condition(s) that would disallow interview’Recruited Hospital/EDWhole sampleN = 1867Mean NR (Median = 23.0)Gender: 41.8% maleTreatment groupN = 922Mean NRGender: 40% maleControl groupN = 945Mean NRGender: 43.3% maleBrief contact intervention1 1-hour information session plus 9 phone calls or visits.Length: Up to 10 contacts over 18 monthsDeveloped study authors (based on existing BIC methods)Delivered doctor, nurse or psychologistTAU: varied between sites, primarily acute injury management with or without mental health referral.Random sequence generation Random numbers tableAllocation concealment Offsite researcherAscertainment of SH InterviewOutcome assessor NRLess than 15% drop-out Yes (11.0%)Was ITT analysis NRSA (dichotomous): European Parasuicide Study Interview Schedule (EPSIS) of the WHO/EURO Multicenter Study on Suicidal BehaviorLongest follow-up: Post-intervention onlyByford et al. (1999) [43]UKInclusion: Diagnosis of SH (self-poisoning)Exclusion: Overdose was accidental; psychiatric condition which would preclude engagement with therapy; social situation precluded engagement with family therapyRecruited MH outpatientWhole sampleN = 162Age/ NRTreatment groupN = 85Age/ NRControl groupN = 77Age/ NRIndividual family therapy plus TAULength: 1 ½ hour assessment plus 1 h of therapyDeveloped study authorsDelivered MH professionalsTAU: routine assessment and psychiatric care in outpatient clinic.Random sequence generation Shuffled cardsAllocation concealment Sealed envelopeAscertainment of SH interviewOutcome assessor YesLess than 15% drop-out Yes (8.0%)Was ITT analysis NRSI (continuous): Suicidal Ideation Questionnaire (SIQ)Longest follow-up: Post-intervention onlyCarter et al. (2010) [44]AustraliaInclusion: Females referred for treatment following self-poisoning, meeting criteria for borderline personality disorder, with at least three self-reported episodes of self-harm over the preceding year.Exclusion: Males, those engaging in self-injury without self-poisoningRecruited MH outpatientWhole sampleN = 70Mean 24.5 (SD: 6.1; Range: 18–65)Gender: 0% maleTreatment groupN = 37Mean 24.5 (SD: 6.1)Control groupN = 33Mean 24.7 (SD: 6.2)Dialectical behavior therapyIndividual and group therapy, with telephone coaching.Length: number of sessions not specified, delivered over six monthsDeveloped based on Linehan et al. (1991)cDelivered MH professionalsTAU + Waitlist: 6 month period of unspecified TAU while waitlisted.Random sequence generation Shuffled envelopesAllocation concealment Sealed, opaque envelopesAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out Yes (0.0%)Was ITT analysis Mixed methodsSH (continuous): Linehan's Lifetime Parasuicide Count–2; Parasuicide History InterviewSH (dichotomous): Linehan's Lifetime Parasuicide Count–2; Parasuicide History InterviewLongest follow-up: Post-intervention onlyCooney et al. (2010) [45]New ZealandInclusion: History of at least one SA or one episode of SH in past three monthsExclusion: i) Intellectual disability; ii) PsychosisRecruited MH outpatientWhole sampleN = 29Mean 15.9 (SD: 1.0; Range: 14–18)Gender: 24.1% maleTreatment groupN = 14Mean 16.2 (SD: 0.98)Gender: 28.6% maleControl groupN = 15Mean 15.7 (SD: 1.1)Gender: 20% maleIndividual plus group dialectical behavioral therapyLength: weekly sessions for approximately 26 weeksDeveloped based on Linehan (1993)d & Miller et al. (2007)eDelivered MH professionalTAU: type and duration CBT, motivational interviewing, supportive counseling, family therapy; medication and case management as needed.Random sequence generation Computer generated algorithmAllocation concealment Sealed, opaque envelopesAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out Yes (0.0%)Was ITT analysis Mixed methodsSI (continuous): BSSISA (dichotomous): Linehan's Suicide Attempt-Self-Injury Interview (SASII)Longest follow-up: Post-intervention onlyCotgrove et al. (1995) [67]UKInclusion: Admitted to hospital following SA/SHExclusion: Records of the original SA were missing, or were there insufficient follow-up data (p. 572)Recruited Hospital/EDWhole sampleN = 105Mean 14.9 (SD: NR; Range: 12.2–16.7)Gender: 15.2% maleTreatment groupN = 4Age/ NRControl groupN = 58Age/ NRBrief contact interventionEmergency card allowing readmission to hospital on request.Length: NADeveloped based on Morgan et al. (1993)fDelivered NATAU: standard follow-up care per ED site.Random sequence generation Open random numbers tableAllocation concealment Use of an open random numbers table suggests allocation could not have been concealedAscertainment of SH Hospital and clinical notesOutcome assessor NALess than 15% drop-out Yes (0.0%)Was ITT analysis NRSA (dichotomous): information collected from clinic and hospital records, and contacting general practitioners and other health professionals involved with young personLongest follow-up: 12 months post-baselineDiamond et al. (2010) [46]gUSAInclusion: i) Scored > 31 on the SIQ-JR (Reynolds, 1987)h; ii) score remained elevated 2 days later following a second screen.Exclusion: i) Current psychosis; ii) mental retardation/history of borderline intellectual functioningRecruited Hospital/ED and primary care practices (75.0% were recruited from primary care and 25.0% from hospitals/EDs)Whole sampleN = 66Mean 15.2 (SD: 1.62; Range 12–17)Gender: 16.7% maleTreatment groupN = 35Mean 15.1 (SD: 1.41)Gender: 8.6% maleControl groupN = 31Mean 15.3 (SD; 1.83)Gender: 25.8% maleIndividual family therapy plus TAULength: Up to 15 sessions delivered over a 3-month periodDeveloped study authorsDelivered trained PhD or Masters level therapistsEnhanced TAU: safety monitoring and facilitated referrals for treatment (incl. Individual, group, or family therapy, or case management).Random sequence generation Adaptive randomizationAllocation concealment Independent researcherAscertainment of SH InterviewOutcome assessor NoLess than 15% drop-out Yes (0.0%)Was ITT analysis YesSI (continuous): SIQ-Junior (SIQ-JR)SI (dichotomous): SIQ-JRLongest follow-up: 3 months post-interventionDonaldson et al. (2005) [47]USAInclusion: Presented to general pediatric child psychiatric hospital after SA.Exclusion: Current psychosisRecruited Hospital/EDWhole sampleN = 39Mean 15.0 (SD: 1.7; Range: 12–17)Gender: 18% maleTreatment N = NRAge/ NRControl N = NRAge/ NRIndividual skills-based therapyiby trained therapistsLength: 12 sessions delivered over 6 monthsDeveloped Study authorsDelivered Trained therapistsEnhanced TAU: Supportive Relationship Treatment (SRT).Random sequence generation Random numbers tableAllocation concealment NRAscertainment of SH InterviewOutcome assessor NRLess than 15% drop-out No (20.5%)Was ITT analysis NoSI (continuous): SIQSA (dichotomous): Structured adolescent follow-up interviewsLongest follow-up: 6 months post-baselineEsposito-Smythers et al. (2011) [48]USAInclusion: SA in past 3 months or scored > 41 on the SIQ (Reynolds, 1987)Exclusion: Verbal IQ score < 70; ii) Psychosis; iv) Bipolar disorder; iv) Dependent on substances other than alcohol or cannabisRecruited MH outpatientWhole sampleN = 40Mean 15.7 (SD: 1.19; Range: 13–17)Gender: 33.3% maleTreatment groupN = 20Mean 15.8 (SD: 0.98)Gender: 31.6% maleControl groupN = 20Mean 15.7 (SD: 1.41)Gender: 35.3% maleIndividual cognitive behavioral therapyLength: 24 sessions delivered over 12 monthsDeveloped based on Donaldson et al. (2005) and Esposito Smythers et al. (2006) and adapted by study authorsDelivered Trained therapistsEnhanced TAU: treatment schedule and approach determined by community providers. Diagnostic evaluation report provided. Study psychiatrist assisted with medication management. Access to information and resources.Random sequence generation Computer generated adaptive randomizationAllocation concealment UnclearAscertainment of SH InterviewOutcome assessor Assessors could guess allocation due to offhand comments made by participants during interviewsLess than 15% drop-out No (25.0%)Was ITT analysis YesSI (continuous): SIQSA (dichotomous): Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS) – clinician administered diagnostic interview.Longest follow-up: 6 months post-interventionGreen et al. (2011) [49]UKInclusion: Presented to child and adolescent services with at least two episodes of SH in the past 12 monthsExclusion: i) Severe low weight anorexia nervosa; ii) psychosis; iii) learning disabilityRecruited MH outpatientWhole sampleN = 366Mean NR (Range: 12–16)Gender: 11.5% maleTreatment groupN = 183Mean NRGender: 11.5% maleControl groupN = 183Mean NRGender: 11.5% maleGroup cognitive behavioral therapyLength: 6 sessions during the acute phase & as many sessions needed during the maintenance phaseDeveloped based on Wood et al. (2001)Delivered Trained therapistsTAU: routine care provided by local child & adolescent mental health services according to clinical judgment, excluding group interventions.Random sequence generation Computer generated minimization algorithmAllocation concealment Independent, off-site researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out Yes (4.0%)Was ITT analysis NoSI (continuous): SIQ-JRSI (dichotomous): SIQ-JRSH (dichotomous): SIQ-JRLongest follow-up: 12 months post-baselineHarrington et al. (1998) [50]jUKInclusion: Presented to hospital with self-poisoningExclusion: i) Other SH (e.g. cutting); ii) Severe suicidality; iii) clinician determined risk of contraindication for family treatment, e.g. psychosis, currently receiving psychiatric treatment, parent/child had a learning difficultyRecruited MH outpatientWhole sampleN = 162Mean 14.5 (SD: 1.15; Range: 10–16)Gender: 10.5% maleTreatment groupN = 85Mean 14.4 (SD: 1.2)Gender: 10.6% maleControl groupN = 77Mean 14.6 (SD: 1.1)Gender: 10.6% maleFive sessions of family therapy plus TAULength: NRDeveloped study authorsDelivered 2 experienced masters'-level child psychiatric social workersTAU: routine psychiatric aftercare including diverse range of interventions, but no home-based family interventions.Random sequence generation Shuffled envelopesAllocation concealment Sealed, opaque envelopesAscertainment of SH InterviewOutcome assessor Attempted but not always possibleLess than 15% drop-out Yes (8.0%)Was ITT analysis NoSI (continuous): SIQSI (dichotomous): SIQSuicide: NRLongest follow-up: 12 months post-baselineHassanian-Moghaddam et al. (2011) [68]IranInclusion: Presented to hospital with self-poisoningExclusion: PsychosisRecruited Hospital/EDWhole sampleN = 2133Mean 24.1 (SD: 8.11; Range: NR)Gender: 33.7% maleTreatment groupN = 1043Mean 24.7 (SD: 7.97)Gender: 33.3% maleControl groupN = 1070Mean 24.1 (SD: 8.25)Gender: 34% maleBrief contact intervention (Postcards from Persia) plus TAU.Length: 8 postcards mailed over 12 monthsDeveloped based on Carter et al. (2005)kDelivered NATAU: follow-up care for self-poisoning in Tehran is “poor”, contact is mainly hospital- or office-based.Random sequence generation Block randomization using a random numbers tableAllocation concealment Allocation was concealed, but information on the method used was not providedAscertainment of SH InterviewOutcome assessor NoLess than 15% drop-out Yes (8.1%)Was ITT analysis NoSI (continuous): follow-up interviewSI (dichotomous): follow-up interviewSH (continuous): follow-up interviewSH (dichotomous): follow-up interviewSA (continuous): follow-up interviewSA (dichotomous): follow-up interviewSuicide: mortality recordsLongest follow-up: 12 months post-baselineHazell et al. (2009) [51]AustraliaInclusion: Presented to hospital with > 2 episodes of SHExclusion: i) Acute psychosis; ii) intellectual disabilityRecruited MH outpatientWhole sampleN = 72Mean 14.5 (SD: 1.1; Range 12–16)Gender: 9.7% maleTreatment groupN = 35Mean 14.6 (SD: 1.1)Gender: 8.6% maleControl groupN = 37Mean 14.4 (SD: 1.2)Gender: 10.8% maleGroup based cognitive behavioral therapy (Moving on from self-harm) plus TAULength: 6 sessions over 12 monthsDeveloped study authorsDelivered MH professionalsTAU: routine care varied but generally included individual/family counseling, medication assessment, and care-coordination.Random sequence generation Block randomization using a computer generated random numbers tableAllocation concealment Independent, offsite researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out Yes (0.0%)Was ITT analysis Mixed methodsSI (continuous): SIQSH (dichotomous): Linehan's Parasuicide History InterviewLongest follow-up: 12 months post-baselineHuey et al. (2004) [52]USAInclusion: Presented to hospital with SA/SIExclusion: Autism spectrum disorderRecruited Hospital/EDWhole sampleN = 156Mean 12.9 (SD: 2.1; Range 10–17)Gender: 35% maleTreatment groupN = UnclearAge/ NRControl groupN = UnclearAge/ NRMulti-systematic family therapyLength: UnclearDeveloped Henggeler et al. (2002)lDelivered MH professionalsActive hospitalization at youth inpatient psychiatric unit.Random sequence generation NRAllocation concealment NRAscertainment of SH InterviewOutcome assessor NALess than 15% drop-out UnclearWas ITT analysis NRSI (dichotomous): Youth Risk Behavior Survey (YRBS)SA (dichotomous): Child Behavior Checklist (CBCL)Longest follow-up: 12 months post-interventionHusain et al. (2014) [53]PakistanInclusion: Admitted to hospital following SHExclusion: i) dementia; ii) substance misuse; iii) organic mental disorder; iv) delirium; v) alcohol and/or drug dependence; vi) schizophrenia; vii) bipolar disorder; viii) intellectual disabilityRecruited Hospital/EDWhole sampleN = 221Mean 23.1 (SD: 5.5; Range: 16–64)Gender: 31.2% maleTreatment groupN = 108Mean 23.2 (SD: 5.8)Gender: 29.6% maleControl groupN = 113Mean 23.1 (SD: 5.3)Gender: 32.7%Individual cognitive behavioral therapy (Life After Self-harm) plus TAULength: 6 sessions over 3 monthsDeveloped based on Schmidt & Davidson (2004)m and adapted by study authorsDelivered masters-level psychologistsTAU: standard routine care provided by local services.Random sequence generation Computer generated random numbers tableAllocation concealment Independent, offsite researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out Yes (3.6% by the 6-month follow-up period; could not calculate for final follow-up)Was ITT analysis YesSI (continuous): BSSISuicide: Not statedLongest follow-up: 6 months post-baselineKing et al. (2006) [54]USAInclusion: i) SA or severe SI in past 3 months ii) Score of 20 or 30 on the Self-Harm subscale of the Child and Adolescent Functional Assessment Scale (Hodges, 1989)nExclusion: i) Severe intellectual disability; ii) PsychosisRecruited Hospital/EDWhole sampleN = 289Mean 15.3 (SD: 1.5; Range: 12–17)Gender: 31.8% maleTreatment groupN = 151Mean 15.4 (SD: 1.5)Gender: 31.1% maleControl groupN = 138Mean 15.2 (SD: 1.4)Gender: 32.6% maleSupportive interventionYouth nominated support team Version 1 plus TAUOne-off brief psycho-education intervention for support team plus up to 9 contacts per week between adolescent and support teamLength: 1.5 to 2 hDeveloped study authorsDelivered MH professionalTAU: varied, included psychotherapy, medication, alcohol/drug treatment, partial hospitalization, and community services.Random sequence generation Random numbers tableAllocation concealment Independent researcherAscertainment of SH InterviewOutcome assessor NoLess than 15% drop-out Yes (18.3%)Was ITT analysis YesSI (continuous): SIQ-JRSI (dichotomous): SIQ-JRSA (dichotomous): Not statedLongest follow-up: 6 months post-baselineKing et al. (2009) [55]USAInclusion: SA or severe SI in past 4 weeksExclusion: NRRecruited Hospital/EDWhole sampleN = 448Mean 15.6 (SD: 1.31; Range: 13–17)Gender: 28.8% maleTreatment groupN = 223Mean 15.6 (SD: 1.24)Gender: NRControl groupN = 225Mean 15.6 (SD: 1.37)Gender: NRSupportive interventionYouth nominated support team Version 2 plus TAUOne-off, individual or group-based (as preferred) psycho-education session plus weekly telephone contacts.For weekly sessions by telephone or face-to-face as preferred with support team.Length: 1 hDeveloped study authorsDelivered MH professionalTAU: as above.Random sequence generation Block randomization using a computer generated sequenceAllocation concealment Independent researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out rate No (23.0%)Was ITT analysis Mixed methodsSuicide: Not statedSA (dichotomous): Clinician administered diagnostic interview DISC-IV Mood Disorders moduleLongest follow-up: 12 months post-baselineKing et al. (2015) [56]USAInclusion: Presented to ED with SI, a recent SA or positive screens for both depression plus alcohol/drug abuseExclusion: Required referral for inpatient psychiatric hospitalizationRecruited Hospital/EDWhole sampleN = 49Mean 17.7 (SD: 1.7; Range: 14–19)Gender: 40% maleTreatment groupN = 27Age/ NRControl groupN = 22Age/ NRIndividual motivational interview plus TAULength: 35–45 minDeveloped study authors (based on standard motivational interviewing protocols)Delivered trained therapistsEnhanced TAU: adolescents given a crisis card and written information about depression, suicide, firearm safety, and services.Random sequence generation Shuffled envelopesAllocation concealment NRAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out Yes (6.1%)Was ITT analysis YesSI (continuous): SIQ-JRLongest follow-up: 2 months post-baselineMcLeavey et al. (1994) [57]Republic of IrelandInclusion: Presented to ED with self-poisoningExclusion: i) Required psychiatric inpatient/day-hospital admission; ii) Psychosis; iii) Intellectual disability; iv) organic cognitive impairmentRecruited Hospital/EDWhole sampleN = 39Mean 24.4 (SD: 7.0; Range 15–45)Gender: 25.6% maleTreatment groupN = 19Mean 23.6 (SD: 5.9)Gender: 21% maleControl groupN = 20Mean 25.3 (SD: 8.1)Gender: 30% maleIndividual Interpersonal Problem-Solving Skills TrainingLength: Five weekly one-hour sessions for 5 weeks (with 1 additional session if necessary)Developed study authorsDelivered MH professionalsActive brief problem-oriented approach, did not involve skills training.Random sequence generation NRAllocation concealment NRAscertainment of SH GP questionnaire and hospital recordsOutcome assessor NALess than 15% drop-out No (15.4%)Was ITT analysis Not describedSH (dichotomous): ED readmissionSuicide: Hospital recordsLongest follow-up: 12 months post-interventionMehlum et al. (2016) [58]oNorwayInclusion: Referred to child & adolescent psychiatric outpatient clinic with a history of > 2 episodes of self-harm; 1 within the past 16 weeksExclusion: i) Bipolar disorder (except bipolar II); ii) Schizophrenia; iii) Affective disorder; iv) Psychosis NOS; v) Intellectual disability; vi) Asperger's syndromeRecruited MH outpatient & Hospital/EDWhole sampleN = 77Mean 15.6 (SD: 1.6; Range: 12–18)Gender: 11.7% maleTreatment groupN = 39Mean 15.9 (SD: 1.4)Gender: 12.8% maleControl groupN = 38Mean 15.3 (SD: 1.6)Gender: 20.5% maleIndividual and group Dialectical Behavior TherapyLength: 19 weeks – One 1-hour weekly session of individual therapy; one 2-hour weekly session of multifamily skills training; plus family therapy & telephone coaching as needed.Developed Miller et al. (2007)Delivered MH professionalsEnhanced TAU: standard care enhanced for the purpose of the trial by requiring that therapists agree to provide at least 1 weekly treatment session per patient.Random sequence generation Block randomization using a computer generated sequenceAllocation concealment Independent researcherAscertainment of SH Interview supplemented with hospital recordsOutcome assessor NALess than 15% drop-out Yes (2.6% by the one-year follow-up period)Was ITT analysis YesSI (continuous): SIQ-JRSH (continuous): ED readmission and self-reportSH (dichotomous): ED readmission and self-reportSuicide: Mortality recordsLongest follow-up: 12 months post-interventionOugrin et al. (2011) [69]; (2013) [39]UKInclusion: Referred to ED following SHExclusion: i) Psychosis; ii) Intoxication; iii) Learning disability; iv) Required inpatient admissionRecruited Hospital/EDWhole sampleN = 70Mean 15.5 (SD: 1.3; Range: 12–18)Gender: 20% maleTreatment groupN = 35Mean 15.6 (SD: 1.5)Gender: 20% maleControl groupN = 35Mean 15.5 (SD: 1.2)Gender: 20% maleBrief contact interventionComprised psychosocial history & risk assessment plus brief interventionLength: 1 h plus 30 minDeveloped study authorsDelivered MH professionalsTAU: standard psychosocial history and risk assessment, report sent to relevant community teamRandom sequence generation Block randomization using a computer generated sequenceAllocation concealment Independent researcherAscertainment of SH Interview supplemented with clinical recordsOutcome assessor NALess than 15% drop-out Yes (1.4% by the two-year follow-up period)Was ITT analysis YesSH (dichotomous): ED readmissionLongest follow-up: 24 months post-baselinePineda & Dadds, (2013) [59]AustraliaInclusion: Presented to ED with either SI, SA or SH within the 2 months prior to presentationExclusion: 1) Overdose of recreational drugs; ii) Intellectual disabilityRecruited EDWhole sampleN = 48Mean 15.1 (SD: 1.2; Range: 12–17)Gender: 25% maleTreatment groupN = 24Mean 15.0 (SD: 1.31)Gender: 27.3% maleControl groupN = 24Mean 15.28 (SD: 1.18)Gender: 22.2% maleStrengths-based family education program plus TAU: Resourceful Adolescent Parent Program (RAP-P)Length: Four 2-hour sessions delivered in a single family format either once a week or once every two weeks. A total of five, 2-hour sessions were provided over up to 2.5 months.Developed based on Shochet et al. (1997)p and adapted by study authorsDelivered primary authorTAU: routine care (included any intervention deemed necessary by the treating team other than RAP-P).Random sequence generation Random numbers tableAllocation concealment Independent researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out No (16.7%)Was ITT analysis YesSI (continuous): ASQ-RLongest follow-up: 6 months post-baselinePower et al. (2003) [60]AustraliaInclusion: Referred to a specialist first episode psychosis clinic with SI or SAExclusion: NRRecruited MH outpatientWhole sampleN = 56Age/ NRTreatment groupN = 31Age/ NRControl groupN = 25Age/ NRIndividual cognitive oriented therapy (Lifespan) plus TAULength: Eight to ten sessions over 10 weeks*.Developed study authorsDelivered MH professionalsTAU: standard clinical care.Random sequence generation NRAllocation concealment NRAscertainment of SH Clinical recordsOutcome assessor NALess than 15% drop-out No (37.5%)Was ITT analysis NRSuicide: Not statedLongest follow-up: Post-intervention onlyRobinson et al. (2012) [70]AustraliaInclusion: Referred but not accepted to a specialist outpatient adolescent MH service with a history of SI, SA or SHExclusion: i) Intellectual disability; ii) Known organic cause for presentationRecruited MH outpatientWhole sampleN = 164Mean 18.6 (SD: NR; Range: 15–24)Gender: 35.4% maleTreatment groupN = 81Mean NRGender: 39.5% maleControl groupN = 83Mean NRGender: 31.3% maleBrief contact intervention plus TAU – monthly postcardsLength: Twelve postcards over 12 monthsDeveloped study authors (based on existing BIC methods)Delivered NATAU: treatment or support already being received; e.g., from school counselor, GP, psychologist.Random sequence generation Block randomization using a computer generated sequenceAllocation concealment Independent researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out No (52.7%)Was ITT analysis No. However, sensitivity analyses were undertaken which suggested that ITT results with data imputed for all missing observations not materially different to per protocol analysisSI (continuous): BSSISI (dichotomous): BSSISH (dichotomous): Suicide Behavior Questionnaire-14 item version (SBQ-14)SA (dichotomous): SBQ-14Longest follow-up: 6 months post-interventionRossouw & Fonagy, (2012) [61]UKInclusion: Presented to ED or referred to community MH services with SHExclusion: i) Presentation the result of excessive use of recreational drugs; ii) Psychosis; iii) Severe learning disability; iv) Developmental disorder; v) Eating disorder; vi) Dependence on alcohol/drugsRecruited Hospital/ED and MH outpatientWhole sampleN = 80Mean 14.7 (SD: 1.25; Range: 12–17)Gender: 15% maleTreatment groupN = 40Mean 15.4 (SD: 1.3)Gender: 17.5% maleControl groupN = 40Mean 14.8 (SD: 1.2)Gender: 12.5% maleMentalization comprised weekly individual sessions plus monthly family therapy.Length: 1 yearDeveloped study authorsDelivered MH professionals.TAU: routine care provided by community-based adolescent mental health services. Mainly individual therapeutic intervention, combined individual and family therapy, or psychiatric review.Random sequence generation Minimization algorithmAllocation concealment Independent, offsite researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out Yes (11.2%)Was ITT analysis YesSuicide: Not statedSH (continuous): Risk-Taking and Self-Harm Inventory (RTSHI)SH (dichotomous): RTSHILongest follow-up: Post-intervention onlyRudd et al. (1996) [40]qUSAInclusion: Referred to outpatient mental health clinics, an inpatient service or an ED with SA, SIExclusion: i) Substance abuse/dependence ii) Psychosis/thought disorder; iii) Personality disorderRecruited Hospital/ED and MH outpatientNB: Setting comprised ^1^y medical centerWhole sampleN = 264Mean 22.2 (SD: 2.3; Range: NR)Gender: 82.2% maleTreatment groupN = 143Mean NRGender: 77.6% maleControl groupN = 121Mean NRGender: 87.6% maleGroup-based problem-solving and social competence trainingLength: 9 h a day for two weeksDeveloped study authorsDelivered MH professionalsTAU: combination of inpatient and outpatient care.Random sequence generation Sequential randomizationAllocation concealment NRAscertainment of SH InterviewOutcome assessor NRLess than 15% drop-out No (73.1% by the 12 month follow-up period)Was ITT analysis UnclearSI (continuous): Modified Scale for Suicidal Ideation (MSSI)rLongest follow-up: Post-intervention onlySlee et al. (2008) [62]sThe NetherlandsInclusion: Presented to an outpatient MH service with recent SHExclusion: Psychiatric disorder requiring inpatient treatmentRecruited MH outpatientWhole sampleN = 82Mean 24.6 (SD: 5.4; Range: 15–35)Gender: 6.1% maleTreatment groupN = 40Mean 23.9 (SD: 6.4)Gender: 2.5% maleControl groupN = 42Mean 25.4 (SD: 4.5)Gender: 9.5% male12 out-patient, individual cognitive behavioral therapy sessions plus TAULength: weekly sessions for up to 5.5 monthsDeveloped NR (but based on standard CBT protocol)Delivered MH professionalsTAU: participants' choice, three psychotropic medication, psychotherapy and psychiatric hospitalizationsRandom sequence generation Computer generated random numbers tableAllocation concealment Independent, offsite researcherAscertainment of SH InterviewOutcome assessor NR.Less than 15% drop-out No (21.0%)Was ITT analysis Mixed methodsSH (continuous): Structured clinical interviewSH (dichotomous): Structured clinical interviewLongest follow-up: 9 months post-baselineSpirito et al. (2002) [71]USAInclusion: Presented to an ED/pediatric hospital with SAExclusion: NRRecruited Hospital/EDWhole sampleN = 63Mean 15.0 (1.4; Range: 12–18)Gender: 9.5% maleTreatment groupN = 29Mean NRGender: 13.8% maleControl groupN = 34Mean NRGender: 5.9% maleBrief contact interventionIndividual compliance enhancement intervention plus TAULength: one hourDeveloped study authorsDelivered post-doctoral psychology fellowsTAU: standard disposition planning.Random sequence generation Random numbers tableAllocation concealment NRAscertainment of SH InterviewOutcome assessor NRLess than 15% drop-out No (17.1%)Was ITT analysis NoSH (dichotomous): Structured interviewSuicide: Not statedLongest follow-up: 3 months post-baselineSpirito et al. (2015) [72]USAInclusion: Resided in a specific catchment plus current or past ‘suicidality’Exclusion: NRRecruited MH outpatient and Hospital/EDWhole sampleN = 24Mean 14.3 (SD: 1.7; Range: 11–17)Gender: 16.7% maleTreatment groupN = 16Mean 14.7 (SD: 1.8)Gender: 12.5% maleControl groupN = 8Mean 14.0 (SD: 1.7)Gender: 25% maleParent-Adolescent-cognitive behavioral therapyIndividual CBT (for the parents plus adolescents) and family sessionsLength: 12 sessions over 12 weeksDeveloped based on protocols used in prior clinical trials with depressedAdolescents.Delivered masters and PhD level cliniciansActive adolescent-only CBT.Random sequence generation NRAllocation concealment NRAscertainment of DSH InterviewOutcome assessor NRLess than 15% drop-out UnclearWas ITT analysis YesSI (continuous): BSSI-ALongest follow-up: 12 months post-baselineNot included in MA^2^Wharff et al. (2017) [63]USAInclusion: i) presentation to ED with “suicidality” or suicide attempt; ii) presence of consenting parent or legal guardianExclusion: i) not fluent in English; ii) Not medically stable, including intoxication; iii) cognitive ‘limitations’ preventing completion of research instruments; iv) active psychosis; v) required physical or medical restraint in EDRecruited Hospital/EDWhole sampleN = 142Mean 15.5 (SD: 1.4)Gender: 28% maleTreatment groupN = 68Mean 15.4 (SD: 1.3)Gender: 26% maleControl groupN = 71Mean 15.6 (SD: 1.5)Gender: 30% maleFamily Based Crisis Intervention (based on cognitive behavioral therapy) plus TAU; an emergency crisis interventionLength: 60 to 90-minDeveloped study authorsDelivered master's level psychiatric social workersTAU: standard psychiatricEvaluation and clinical/discharge recommendations.Random sequence generation NRAllocation concealment NRAscertainment of DSH NAOutcome assessor NALess than 15% drop-out Yes (19.0%)Was ITT analysis NoSI (continuous): Reasons for Living Inventory for Adolescents (RFL-A)tLongest follow-up: 1 month post-interventionWood et al. (2001) [64]UKInclusion: i) Referred to child & adolescent MH service following SH; ii) Engaged in SH on at least one other occasion during the past yearExclusion: i) ‘Too suicidal’ for ambulatory care; ii) psychosis; iii) learning ‘problems’Recruited MH outpatientWhole sampleN = 63Mean 14.3 (SD: 1.6; Range: 12–16)Gender: 22.2% maleTreatment groupN = 32Mean 14.2 (SD: 1.1)Gender: 21.9% maleControl groupN = 31Mean 14.3 (SD: 2.1)Gender: 25.8% maleCombined group-based psychotherapy plus TAU. Comprised aspects of cognitive behavioral therapy, dialectical behavioral therapy and psychodynamic psychotherapy.Length: “until the young person feels ready to leave” (p. 1247).Developed study authorsDelivered MH professionalsTAU: variety of interventions delivered by community psychiatric nurses & psychologists. Included family sessions, nonspecific counseling. Psychotropic medication (where indicated).Random sequence generation Random numbers tableAllocation concealment Independent, offsite researcherAscertainment of SH InterviewOutcome assessor YesLess than 15% drop-out Yes (3.1%)Was ITT analysis YesSH (continuous): ED readmission (assessed via interview)SH (dichotomous): ED readmissionSuicide: Not statedLongest follow-up: 7 months post-randomizationNotes: ED = Emergency Department; ITT = intention-to-treat; IQR = Interquartile Range; MA = meta-analysis; MH = mental health; NR = not reported; TAU = treatment as usual; SA = suicide attempt; SD = standard deviation; SH = self-harm; SI = suicidal ideation; SRB = suicide-related behavior.aStanley B, et al. Cognitive behavioral therapy for suicide prevention (CBTSP): treatment model, feasibility and acceptability. J Am Acad Child Adolesc Psychiatry 2009; 48 [10]:1005–13.bRotheram-Borus MJ, et al. Enhancing treatment adherence with aspecialized emergency room program for adolescent suicide attempters. J Am Acad Child Adolesc Psychiatry 1996; 654–663.cLinehan MM, et al. Cognitive-behavioral treatment of chronically parasuicidal borderline patients. Arch Gen Psychiatry 1991; 1060–1064.dLinehan MM. Skills training manual for treating borderline personality disorder. New York: Guilford Press, 1993.eMiller, AL, et al. Dialectical behavior therapy with suicidal adolescents. New York: Guilford Press, 2007.fMorgan HG et al. Secondary prevention of non-fatal deliberate self-harm. The green card study. BJP 1993; 111–112.gExcluded secondary Diamond G, et al. Sexual trauma history does not moderate treatment outcome in Attachment-Based Family Therapy (ABFT) for adolescents with suicide ideation. J Fam Psychol 2012; 26(4): 595-605; Shpigel MS, et al. Changes in parenting behaviors, attachment, depressive symptoms, and suicidal ideation in attachment-based family therapy for depressive and suicidal adolescents. J Marital Fam Ther 2012; 38(Suppl 1): 271-83.hReynolds WM. Suicidal Ideation Questionnaire: Professional Manual. Psychological Assessment Resources Inc., 1987.iClassified as CBT in the meta-analysis.jExcluded secondary Harrington R, et al. Deliberate self-poisoning in why does a brief family intervention work in some cases and not others? J Adolesc 2000; 23(1): 13–20.kCarter GL, et al. Postcards from the EDge randomised controlled trial of an intervention using postcards to reduce repetition of hospital treated deliberate self poisoning. BMJ 2005; 805–7.lHenggeler S, et al. Serious Emotional Disturbance in Children and Adolescents: Multisystemic Therapy. New York: Guilford Press, 2002.mSchmidt U, Davidson KM. Life After Self-Harm: A Guide to the Future. Routledge, 2004.nHodges K. Child and Adolescent Functional Assessment Scale. Ypsilanti: Eastern Michigan University, 1989.oExcluded secondary Mehlum L, et al. Dialectical behavior therapy for adolescents with repeated suicidal and self-harming a randomized trial. J Am Acad Child Adolesc Psychiatry 2014; 53(10): 1082–91.pShochet I, et al. Resourceful Adolescent Parent Program: group leader's manual. Brisbane, Australia: Griffith University, 1997.qExcluded secondary Wingate LR, et al. (Comparison of compensation and capitalization models when treating suicidality in young adults. J Consult Clin Psychol, 2005. 73(4): 756–62.rMiller I, et al. (1986). The modified scale for suicidal Reliability and validity. J Consult Clin Psychol, 54, 724–725.sExcluded secondary Slee N, et al. Emotion regulation as mediator of treatment outcome in therapy for deliberate self-harm. Clin Psychol Psychother 2008; 15(4): 205–16.; Spinhoven P, et al. Childhood sexual abuse differentially predicts outcome of cognitive-behavioral therapy for deliberate self-harm. J Nerv Ment Dis 2009; 197(6): 455–7.tOsman A, et al. The Reasons for Living Inventory for Adolescents (RFL-A): development and psychometric properties. J Clin Psychol 1998; 1063–1078.Table 2Study Non-randomized controlled trials conducted in clinical settings (N = 19).Table 2Study; countryStudy design; level of evidenceTarget populationParticipantsIntervention descriptionComparison conditionRisk of biasSuicide related outcome(s) assessed; Longest follow-upResultsInterpretationAsarnow et al. (2015) [73]USAStudy Pre-test/post-test case seriesLevel of IVInclusion: SA in past 3 months; stable living situationExclusion: No contact information available for follow-up; psychosis; substance abuse/dependence; not English-speaking; no family to participateRecruited Hospital/EDN = 35Mean 14.89 (SD: 1.6; Range: 11–18)Gender: 14% maleSuicide-specific family-based cognitive behavioral therapy comprising psycho-education plus individual therapy.The Safe Alternatives for Teens & Youths program (SAFETY Program)Length: Up to 20 sessions over 12 weeks, 1 × family session then individual (16 x youth-only & parent-only), then up to 16 × family sessionsDeveloped Henggeler (2002)Delivered a MH professionalNAAdequately NROutcome assessor NALess than 15% drop-out Yes (11.4%)Use of statistical testing to measure change from pre-test to post-test: YesSI: Harkavy-Asnis Suicide Survey, passive suicidal ideation subscale.SA: Harkavy-Asnis Suicide Survey, suicide attempt subscale.SRB: Harkavy-Asnis Suicide Survey, active suicidal behavior and ideation subscale.Longest follow-up: 6 months post-interventionSI: Pre-testMean (SD): 12.69 (9.79)Post-test Mean (SD): 9.19 (10.14)SA: Pre-testMean (SD): 0.89 (1.86)Post-test Mean (SD): 0.13 (0.34)SRB: Pre-testMean (SD): 3.71 (4.42)Post-test Mean (SD): 1.81 (2.69)There was evidence of a significant reduction in SI (t-test = 2.56, p = 0.016, Cohen's d = 0.39), SA (t-test = 2.42, p = 0.019), and SRB (t-test = 2.63, p = 0.013) between baseline and three-month follow-up. Four young people either re-attempted suicide and/or re-engaged in NSSI during the treatment period (significance test not reported).Brent et al. (2009) [91]USAStudy Non-randomized, experimental trialLevel of III-2Inclusion: Had major unipolar mood disorder & SA in past 90 days; living with a parent or guardian who could participate in treatmentExclusion: Substance dependence, bipolar disorder, psychosis, or developmental disorderRecruited UnclearWhole sampleN = 124Mean 15.8 (SD: 1.5; Range: 12–18)Gender: 22.6% maleTreatment group (1)N = 18Age/ NRTreatment group (2)N = 93Age/ NRControl groupN = NRAge/ NRSuicide-specific individual cognitive behavioral therapy with some elements of dialectical behavior therapy.Length: between 12 and 16 weekly sessions.Developed Study authorsDelivered UnclearMedication management or combined medication & CBTAdequately NoOutcome assessor YesLess than 15% drop-out No (33.1%)Use of statistical testing to measure change from pre-test to post-test: YesSA: Columbia Classification Algorithm of Suicide AssessmentSRB: Columbia Classification Algorithm of Suicide Assessment.Suicide: not described.Longest follow-up: Post-intervention onlySA: NRSRB: NRSuicide: NRThere was evidence of an increase in SRB between baseline and six-month follow-up in the combination (i.e., psycho- and pharmacotherapy group) compared to either condition alone (22/93 vs. 2/31; Fisher's exact test p = < 0.04). There was one completed suicide after the six-month follow-up, however, it is unclear to which treatment group this young person had been allocated.Courtney & Flament, (2015) [74]CanadaStudy Pre-test/post-test case seriesLevel of IVInclusion: BPD features with SI OR SH in past 4 monthsExclusion: psychosis; developmental disorderRecruited MH outpatientN = 61Mean 16.5 (SD: 0.8; Range: 15–18)Gender: 7% maleDialectical behavior therapy adapted for adolescents in tertiary care. A-DBT-ALength: 1 x weekly group-based and 1 × weekly individual sessions over 14-weeks (session duration not stated).Developed Based on Miller et al. (2006) but adapted by the study authorsDelivered a MH professionalNAAdequately NROutcome assessor NALess than 15% drop-out No (49.2%)Use of statistical testing to measure change from pre-test to post-test: YesSI: Suicidal Ideation Questionnaire (SIQ).SRB: Medical/clinical records.Suicide: NRLongest follow-up: Post-intervention onlySI: Pre-testMedian (IQR): 131.0 (92.0 to 144.0).Post-testMedian (IQR): 77.0 (48.5 to 121.0).SRB: NRSuicide: NRThere was evidence of a significant reduction in SI (t-test = 4.96, p < 0.001, Cohen's d = 0.89) between baseline and the 15-week post-intervention assessment. There was also evidence of a significant reduction in the proportion of young people engaging in SRB over this period (36/42 vs. 16/42, McNemar test p < 0.001). There were no reports of completed suicides.Cwik et al. (2016) [82]USAStudy Pre-test/post-test case seriesLevel of IVInclusion: Apaches with SA in past 90 daysExclusion: noneRecruited Community suicide surveillance systemN = 13Mean 14.3 (SD: 2.2)Gender: 8% maleNew Hope, a brief psycho-education intervention for American Indian adolescentsLength: 1–2 visits (2–4 h total).Developed Study authorsDelivered Community Mental Health WorkersNAAdequately NoOutcome assessor NALess than 15% drop-out No (15.4%)Use of statistical testing to measure change from pre-test to post-test: YesSI: SIQLongest follow-up: 3 monthsPost-interventionSI: N (%) scoring above clinical cut-off: Pre-test: 7/11 (64%)Post-test: 1/10 (10%)The number of participants who scored above the clinical cut-off for the SIQ seemed to decrease over the follow-up period.Diamond et al. (2013) [83]aUSAStudy Pre-test/post-test case seriesLevel of IVInclusion: LGB discharged from hospital with SI (admitted for SI or SA)Exclusion: Psychosis or IDRecruited Hospital/EDN = 10Mean 15.1 (SD: 1.37; Range: 14–18)Gender: 20% maleAttachment-based family therapy adapted for use with suicidal LGB youth. ABFT-LGBLength: 12 x weekly sessions (range = 8–16). Sessions lasted for 60-min & sessions 3–5 were for parents only.Developed Study authorsDelivered a MH professionalNAAdequately NoOutcome assessor NALess than 15% drop-out Yes (0.0%)Use of statistical testing to measure change from pre-test to post-test: YesSI: SIQ-Junior (SIQ-JR)Longest follow-up: Post-intervention onlySI: Pre-test Mean (SD): 51.00 (13.00)Post-testMean (SD): 6.88 (7.34)There was evidence of a significant reduction in SI between baseline and the 3-month post-intervention assessment (F-test = 18.78, p = 0.001, Cohen's d = 0.21).Duarte-Velez et al. (2016) [75]Puerto RicoStudy Pre-test/post-test case seriesLevel of IVInclusion: Admitted to ED with SI or SA, hospitalized, stabilized and referred to outpatient; legal guardian.Exclusion: Psychosis; developmental disorder;ID; already receiving psychotherapy; involvement in alegal procedure that would require psychological care mandated bythe judicial systemRecruited Hospital/EDN = 11Mean 15.36 (SD-NR; Range: 13–17)Gender: 45% maleCognitive behavioral therapy adapted for Puerto Rican adolescents with suicidal behavior.Length: Weekly individual sessions lasting for 1 h & delivered over 6 months. Plus 60–120 min family sessions & follow-up bi-weekly as necessary. Phone calls & case management as needed.Developed Study authorsDelivered a MH professionalNAAdequately NoOutcome assessor NALess than 15% drop-out No (27.3%)Use of statistical testing to measure change from pre-test to post-test: YesSI: SIQ-JRLongest follow-up: Post-interventionSI: Pre-test Mean (SD): 27.20 (NR)Post-testMean (SD): 16.00 (NR)There was evidence of a reduction in SI between baseline and the six month post-intervention assessment (significance test not reported).Esposito-Smythers et al. (2006) [76]USAStudy Pre-test/post-test case seriesLevel of IVInclusion: Admitted to inpatient unit for SI/SA with co-occurring alcohol abuse/dependenceExclusion: ID, DSM-IV dependence on substances other than alcohol or cannabis.Recruited Hospital/EDN = 6Mean 15 (SD: 1; Range: 14–16)Gender: 17% maleIntegrated cognitive behavioral therapy for adolescents with co-occurring alcohol use disorder and suicidality.Length: Acute Weekly sessions lasting 1 h & delivered over 6 months (plus maintenance & booster phases).Developed Study authors, incorporating modifications of Monti's (2002)b coping skills training package for youth with co-occurring alcohol use disorderDelivered a MH professionalNAAdequately NoOutcome assessor NALess than 15% drop-out No (16.7%)Use of statistical testing to measure change from pre-test to post-test: NoSI: SIQSRB: NRLongest follow-up: 12 months post-interventionSI: Pre-testMean (SD): 80.80 (NR)Post-testMean (SD): 32.80 (NR)There was evidence of a reduction in SI between baseline and the 12 month post-intervention assessment (significance test not reported). Two young people re-engaged in SRB during this period (significance test not reported).Geddes et al. (2013) [77]AustraliaStudy Pre-test/post-test case seriesLevel of IVInclusion: At least 3 BPD features & SI/SH in past 12 monthsExclusion: Primary diagnosis of psychosis or substance abuse; IDRecruited MH OutpatientN = 6Mean 15.1 (SD-NR; Range 14–15)Gender: 0% maleDialectical behavior therapy modified for Life SurfingLength: 1–2 weekly sessions lasting for 1 h & delivered over 26 weeks. Plus a weekly 2 h family skills group delivered over an 18-week period.Developed Based on Swales (2000)c but adapted by the study authors.Delivered NRNAAdequately NoOutcome assessor NALess than 15% drop-out No (16.7% by the three-month follow-up period)Use of statistical testing to measure change from pre-test to post-test: YesSI: NRSBR: Self-Harm/Suicidal Thoughts Questionnaire: Parent and Adolescent Versions.SA: NRLongest follow-up: 12 months post-baselineSA: NRSRB: NRThere was evidence of a reduction in the proportion of young people reporting SI between baseline and the 18-week post-intervention assessment (significance test not reported). By the 18-week post-intervention assessment, 5 of the 6 young people had had no further episodes of SRB, whilst the sixth reported a 50% reduction in SRB frequency (significance tests not provided). By the 12 month follow-up period, no young person had a further episode of SA (significance test not reported).Gutstein & Rudd (1990) [78]USAStudy Pre-test/post-test case seriesLevel of IVInclusion: Referred to a guidance center following a near-lethal SA/persistent suicide threats (severe risk)Exclusion: NARecruited Hospital/Ed, MH outpatient & communityN = 47Mean 14.4 (SD-NR; Range: 7–19)Gender: 47% maleA suicide-specific intensive group crisis Systemic Crisis Intervention ProgramLength: Two × 4-hour group meetings over a 2–6 week period.Developed Study authorsDelivered NRNAAdequately NoOutcome assessor NALess than 15% drop-out Yes (0.0%)Use of statistical testing to measure change from pre-test to post-test: NoSA: Parental reportLongest follow-up: Post-intervention onlySA: NRThere was evidence of a reduction in the proportion of young people engaging in SA between baseline and the 18 month follow-up assessment (significance test not reported).James et al. (2011) [79]UKStudy Pre-test/post-test case seriesLevel of IVInclusion: Living in ‘out of home care’ & engaged in SH for > 6 monthsExclusion: diagnosis of schizophrenia,bipolar disorder, autism spectrum disorder;Moderate–severe mental impairmentRecruited MH outpatient serviceN = 25Mean 15.5 SD: 1.5; Range: 13–17Gender: 12% maleDialectical behavior therapy comprising a skills training group, individual therapy, telephone support, support for schools/carers & outreach.Length: 1-hour individual sessions plus 2-hour group sessions delivered weekly over 12 months.Developed Based on Linehan (1993) and Rathus and Miller (2002)d but adapted by the study authors.Delivered a MH professionalNAAdequately NoOutcome assessor NALess than 15% drop-out No (28.0%)Use of statistical testing to measure change from pre-test to post-test: YesSRB: Clinical interviewLongest follow-up: Post-intervention onlySRB: NRThere was evidence of a reduction in the proportion of young people engaging in SRB between baseline and the 12 week post-intervention period (14/18 young people had ceased engaging in SRB altogether) (significance tests not provided). There was also evidence of a reduction in the frequency of these SRB episodes over this period (significance tests not provided).James et al. (2015) [80]UKStudy Pre-test/post-test case seriesLevel of IVInclusion: SH in past 12 monthsExclusion: NRRecruited MH outpatient & communityN = 154Mean 14.9 (SD: 1.3; Range: 12–18)Gender: 14.8% maleDialectical behavior therapy for adolescents Length: Three-hour group sessions delivered twice weekly, plus weekly individual or family sessions, 30–60 min in duration. Delivered over 16 weeks.Developed Based on Miller (2006)Delivered MH professionalNAAdequately NROutcome assessor NALess than 15% drop-out No (30.3%)Use of statistical testing to measure change from pre-test to post-test: YesSRB: Youth Outcome Questionnaire, Self-Report, version 2.0, item 21Longest follow-up: Post-intervention onlySRB: Pre-test Mean (SD): 2.06 (1.68).Post-test Mean (SD): 0.65 (0.98).There was evidence of a significant reduction in SRB between baseline and the 16-week post-intervention assessment (F-test = 68.83, p < 0.001, η^2^ = 0.42).Katz et al. (2004) [84]CanadaStudy Non-randomized, experimental trialLevel of III-2Inclusion: Admitted to Inpatient unit for SA or SIExclusion: ID, severe learning disability, psychosis, bipolar disorderRecruited Hospital/EDWhole sampleN = 62Mean 15.4 (Range: 14–17)Gender: 16.1% maleTreatment groupN = 31Age/ NRControl groupN = 31Age/ NRIndividual & group dialectical behavior therapyLength: 10 daily group sessions plus 4 individual sessions delivered over 2 weeksDeveloped Based on Miller (1997)e but adapted by the study authorsDelivered MH professionalTAU: daily psychodynamic psychotherapy group, weekly individual therapy, and psychodynamically-oriented milieu.Adequately Study authors provide power calculations, however, study unlikely to be adequately powered for SRB.Outcome assessor NALess than 15% drop-out Yes (10.0%)Use of statistical testing to measure change from pre-test to post-test: YesSI: SIQ-JRSuicide: NRLongest follow-up: 1 year post-interventionSI: Post-interventionIntervention mean (SD): 40.90 (24.73)Control mean (SD): 37.97 (24.56)12 months: Intervention mean (SD): 18.15 (12.52)Control mean (SD): 19.25 (17.89)Suicide: NRThere was no evidence of a reduction in SI between the intervention and control groups at post-intervention (40.90 ± 24.73 vs. 37.97 ± 24.56) and at the 12 month follow-up assessment (18.15 ± 12.52 vs. 19.35 ± 17.89). There were no completed suicides in either group by the 12 month follow-up assessment (significance test not reported).King et al. (2003) [81]AustraliaStudy Pre-test/post-test case seriesLevel of IVInclusion: Called helpline and reported SIExclusion: NoneRecruited Telephone helplineN = 101Age: NRGender: UnclearKids helplineSingle crisis phone callLength: Mean duration 40 min; range 10–120 minDeveloped Charitable organizationDelivered trained volunteersNAAdequately NROutcome assessor NALess than 15% drop-out Yes (0.0%)Use of statistical testing to measure change from pre-test to post-test: YesSI: Idiosyncratic, binary-coded instrument adapted from items from the Mini International Neuropsychiatric Interview.Longest follow-up: Post-intervention onlySI: Pre-test Mean (SD): 6.30 (2.22).Post-test Mean (SD): 3.01 (2.43).There was evidence of a significant reduction in SI from the beginning to the end of the call (average call duration 40 min) (t-test = 12.66, p < 0.005, η^2^ = 0.62).Law et al. (2016) [85]Hong KongStudy Non-randomized, experimental trialLevel of III-2Inclusion: Admitted to the ED with SHExclusion: any DSM IV-TR Axis II disorder; psychosis; bipolar disorderRecruited Hospital/EDWhole sampleN = 78Mean NRRange: 18–34Gender: NRTreatment groupN = 40Mean 24.7 (SD: 5.4)Gender: 18.4% maleControl groupN = 38Mean 26.0 (SD: 6.2)Gender: 11.1% maleBrief contact Volunteer mentorshipLength: ≥ 2 contacts per month over 9 months.Developed Study authorsDelivered trained volunteers supervised by psychiatrists, psychologists, and social workersTAU (not described)Adequately Study authors provide power calculations, however, study unlikely to be adequately powered for SRBOutcome assessor NALess than 15% drop-out No (67.6%)Use of statistical testing to measure change from pre-test to post-test: YesSI: SIQSRB: Hospital recordsLongest follow-up: Post-intervention onlySI: Post-intervention: Intervention mean (SD): 20.70 (3.00)Control mean (SD): 15.60 (6.50)SRB: NRThere was no evidence of a significant reduction in SI between the intervention and control groups at post-intervention (20.70 ± 3.00 vs. 15.60 ± 6.50, β = 2.31, SE = 2.52, p > 0.05).There was also no evidence of a reduction in SRB between the intervention and control groups by this time point (4/38 vs. 4/36) (significance test not provided).Oldershaw et al. (2012) [86]UKStudy Retrospective cohort studyLevel of III-2Inclusion: Reported history of SHExclusion: ID; serious head injury; used medication with sedatory side effects; primary diagnosis not depression or SH.Recruited MH outpatient, schools & personal contactsWhole sampleN = 33Mean NR(SD: NR; Range: 12–18)Gender: NRTreatment groupN = 24Age: NRGender: 4.2% maleControlN = 9Age: NRGender: 22.2% maleStandalone, formulation based, and modularized cognitive behavioral therapy with core and optional modules, depending on clinical need.Length: 12 sessionsDeveloped Study authorsDelivered MH professionalNo Participants either declined or did not pursue treatmentAdequately NoOutcome assessor NALess than 15% drop-out Yes (0.0%)Use of statistical testing to measure change from pre-test to post-test: YesSRB: Idiosyncratic, binary-coded instrumentLongest follow-up: 5 months post-baselineSRB: NRThere was evidence of a significant reduction in the proportion of participants engaging in SRB between the intervention and control groups at post-intervention (14/24 vs. 3/9). There was also evidence of a significant reduction in the frequency of SRB by this time point (Z = − 3.20, p < 0.001).Perera Ramani & Kathriarachchi, (2011) [87]Sri LankaStudy Non-randomized, experimental trialLevel of III-2Inclusion: Admitted to hospital for SA; categorized as medium- and low-intentExclusion: Diagnosed with major psychiatric disorderRecruited Hospital/EDWhole sampleN = 124Mean NR(SD: NR; Range: 15–24)Gender: UnclearTreatment groupN = 62Age/Gender: NRControl groupN = 62Age/Gender: NRIndividual problem solving therapyLength: 4 sessions delivered over 1 monthDeveloped Based on Palmer (1995)fDelivered MH professionalTAU: routine care (referral to a medical officer, psychiatric referral, referrals to other agencies).Adequately NoOutcome assessor NRLess than 15% drop-out No (18.5%)Use of statistical testing to measure change from pre-test to post-test: NoSA: NRLongest follow-up: 6 months post-baselineSA: NRThere was a reduction in the proportion of participants engaging in SA between the intervention and control groups at post-intervention (0/55 vs. 2/46) (significance test not reported).Rathus & Miller, (2002) [88]USAStudy Non-randomized, experimental trialLevel of III-2Inclusion: SA or SI in past 4 months AND Borderline Personality Disorder featuresExclusion: NRRecruited MH outpatientWhole sampleN = 111Age: NRGender: 21.6% maleTreatment groupN = 29Mean 16.1 (SD: 1.2; Range: NR)Gender: 7% maleControl groupN = 82Mean 15.0 (SD: 1.7; Range: NR)Gender: 27% maleDialectical behavior therapy adapted for adolescents.Length: Two sessions per week for 12 weeksDeveloped Based on Linehan (1993) but adapted for adolescents by study authorsDelivered MH professionalActive Short term psychodynamic or supportive approach aimed at resolving acute problems.Adequately NoOutcome assessor NALess than 15% drop-out UnclearUse of statistical testing to measure change from pre-test to post-test: YesSI: Beck Scale for Suicidal Ideation (BSSI)SA: Self-reportLongest follow-up: 3 months post-interventionSI: Pre-test Mean (SD): 9.80 (5.30)Post-test Mean (SD): 3.80 (4.60)SA: NRThere was a significant reduction in SI between baseline and the 12-week post-intervention assessment (t-test = 2.65, p = 0.26). There was also evidence of a reduction in SA between the intervention and control groups by the 12-week post-intervention assessment (1/29 vs. 7/82).Rotheram-Borus et al. (1996) [89]; (2000) [35]USAStudy Historical controlled studyLevel of III-3Inclusion: Presented to ED with SA & hospitalized for < 1 weekExclusion: Low IQ, no parent or familyRecruited Hospital/EDWhole sampleN = 140Mean 15.0 (SD: NR; Range: 12–18)Gender: 0% maleTreatment groupN = 65Mean 15.0 (SD: 1.4)Control groupN = 75Mean 15.3 (SD: 1.6)Specialized Emergency Room Program: Comprised 1 family psychotherapy session plus psycho-education video.Length: Session = NR; video = 20 minDeveloped Study authorsDelivered MH professionalTAU: evaluation to determine if hospitalization required & referral to outpatient therapy.Adequately Likely to be adequately powered for SI.Outcome assessor NALess than 15% drop-out Yes (0.0%)Use of statistical testing to measure change from pre-test to post-test: YesSI: Harkavy-Asnis Suicide Survey, passive suicidal ideation subscaleSA: Self- and parental-report in conjunction with hospital recordsLongest follow-up: 18 months post-suicide attemptSI: Post-intervention: Intervention mean (SD): 1.40 (2.38)Control mean (SD): 2.10 (2.86)SA: 18-month follow-up: Tx – 6/65 participants reattempted; Control – 11/75 participants reattemptedThere was evidence of a significant reduction in SI between the intervention and control groups by the post-intervention assessment (p < 0.001). There was also evidence of a reduction in SA between the intervention and control groups by the 18 month follow-up assessment (significance test not reported).Wharff et al. (2012) [90]USAStudy Historical controlled studyLevel of III-3Inclusion: Presented to the ED with SRBExclusion: not living with family; presented to ED without a family member; intoxicated/sedated at time of presentation; psychosis or developmental delay; presented during overnight shift or on weekendRecruited Hospital/EDWhole sampleN = 250Mean NR (SD: NR; Range: 13–18)Gender: 29% maleTreatment groupN = 100Mean 15.6 (SD: 1.5)Gender: 24% maleControl groupN = 150Age: NRGender: 26% maleOne session of family based crisis interventionDeveloped Study authorsLength: NRDelivered MH professionalTAU: retrospective comparison group who presented to the same ER prior to implementation of FBCI.Adequately NoOutcome assessor UnclearLess than 15% drop-out No (44.6%)Use of statistical testing to measure change from pre-test to post-test: NoSRB: NRSA: NRSuicide: NRLongest follow-up: 3 months post-interventionSRB: NRSA: NRSuicide: NRThere were no episodes of SA or completed suicide in either the intervention or control group by the three month follow-up period. Two participants (unclear if allocated to intervention or control groups) were hospitalized for SRB by the three month follow-up assessment.Notes: ED = Emergency Department; ID = Intellectual Disability; ITT = intention-to-treat; IQR = Interquartile Range; MH = mental health; NR = not reported; TAU = treatment as usual; SA = suicide attempt; SD = standard deviation; SH = self-harm; SI = suicidal ideation; SRB = suicide-related behavior.aCorrected version of the same paper published in 2012.bMonti PM, et al. Treating Alcohol Dependence: A Coping Skills Training Guide. 2nd ed. New York, NY: Guilford Press; 2002.cSwales M, et al. Linehan's Dialectical Behaviour Therapy (DBT) for borderline personality overview and adaptation. J Ment Health 2000; 9(1): 7–23.dRathus J, Miller A. Dialectic behavior therapy adapted for suicidal adolescents. Suicide Life Threat Behav 2002; 146–157.eMiller AL, et al. Dialectical behavior therapy adapted for suicidal adolescents. J Pract Psychiatry Behav Health 1997; 78–86.fPalmer S, Dryden W. Counseling for Stress Problems. New Delhi: Sage Publications, 1995.Table 3Study Randomized controlled trials conducted in educational or workplace settings (N = 15).Table 3Study; countryTarget populationParticipantsIntervention descriptionComparison conditionRisk of biasSuicide related outcome(s) assessed; longest follow-upUniversal interventionsGuille et al. (2015) [113]USAInclusion: Medical students beginning their internship in July 2009 or July 2011 at one of two participating university hospitalsExclusion: NRRecruited Universities (N = 2)Whole sampleN = 199Mean 25.2 (SD: 8.1; Range: NR)Gender: 50.7% maleTreatment groupN = 100Mean 24.9 (SD: 8.7)Gender: 49% maleControl groupN = 99Mean 25.4 (SD: 7.4)Gender: 51.6% maleIndividual access to MoodGym: online Cognitive Behavioral Therapy.Module Understanding the interplay between thoughts, emotions & behavior. Modules 2–3: Cognitive restructuring. Module Problem-solving.Length: Four 30-min modulesDeveloped National Institute for Mental Health Research at The Australian National UniversityDelivered Self-directedActive Email once a week for 4 weeks with information about depression, suicide & where to seek treatment.Random sequence generation NRAllocation concealment Independent researcherAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out Yes (0.0%)Was ITT analysis YesSI (dichotomous): Item 9 of the Patient Health Questionnaire-9 (PHQ-9)Longest follow-up: 12 months post-interventionOrbach & Bar-Joseph, (1993) [92]IsraelInclusion: High school juniors from six schoolsExclusion: NoneRecruited Secondary schools (N = 6)Whole sampleN = 393Mean NRGender: 45% maleTreatment groupN = 215Age/ NRControl groupN = 178Age/ NRWeekly group psycho-educationworkshops: 1) Depression & happiness 2) The individual & their family 3) Helplessness 4) Coping with failure 5) Coping & problem solving 6) Coping with suicidal urges 7) SummaryLength: Seven 2-hour workshopsDeveloped based on Ross (1997)a and adapted by study authors.Delivered NRTAU: social issues discussion classRandom sequence generation NRAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out Yes (0.0%)Was ITT analysis Mixed methodsSI (continuous): Israeli Index of Potential Suicide (IIPS)Longest follow-up: Post-intervention onlyTill et al. (2017) [119]AustriaInclusion: medical, psychology and communication studies undergraduate studentsExclusion: NoneRecruited University (N = 1)Whole sampleN = 161Mean 24.5 (SD 5.8)Gender: 32.9% maleTreatment groupN = 121Mean 24.3 (SD NR)Gender: 33.9% maleControl groupN = 40Mean 25.0 (SD 6.8)Gender: 30% malePsychoeducation plus supportThree German-language websites on suicide-related education and prevention. Two of the three websites also offered email counseling by peers.Length: NADeveloped mental health organizationsDelivered Self-directedA website unrelated to suicide or mental healthRandom sequence generation NRAllocation concealment NRAscertainment of DSH NAOutcome assessor NALess than 15% drop-out UnclearWas ITT analysis YesSI (continuous): Reasons for Living Inventory (RFLI)Longest follow-up: Post-intervention only

Indicated interventionsEggert et al. (2002)b[95],USAInclusion: Students who screened positive for SRBExclusion: NoneRecruited Secondary schools (N = 7)Whole sampleN = 341Mean age (SD): NR(Range: 14–19)Gender: 48% maleTreatment group 1 (C-CAST)N = 103Mean 16.02 (SD: 1.14)Gender: 40.77% maleTreatment group 2 (C-Care)N = 117Mean 15.71 (SD: 1.21)Gender: 52.14% maleControl groupN = 121Mean 15.62 (SD: 1.26)Gender: 50.83 maleSupportive intervention 1)C-CARE: One individual assessment interview followed by one counseling session & social connections intervention with parents and school staff2)C-CARE plus a small group prevention program.Length:1)2-hour assessment plus one 1.5–2 h counseling;2)Additional 12 × 1 hour sessions over 6 weeksDeveloped study authorsDelivered 1) Trained research staff e.g. practice nurses & social workers; 2) Teachers, counselors or nursesTAU: a brief assessment interview and social connections intervention with parents and school personnel.Random sequence generation Block randomization using a predetermined sequenceAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out: No (20.5%)Was ITT analysis NoSRB: High School Questionnaire: Profile of Experiences (HSQ)Longest follow-up: 9 months post-baselineNot included in MAFitzpatrick et al. (2005) [115]USAInclusion: Students who screened positive for SIExclusion: students who were judged to represent an immediate threat of danger to themselves or othersRecruited University(N = 1)Whole sampleN = 110Mean 19.02 (SD: 1.21; Range: 18–24)Gender: 45% maleTreatment NRControl NRA one-off suicide-specific problem solving intervention. Included a video, narrated Power-Point presentation & a case study. Included identifying problems and cognitive, behavioral & affective reactions. It encouraged participants to elicit their problems and apply the skills learned in the video to their personal problems.Length: 40 minsDeveloped based on D'Zurilla and Nezu (1999)cDelivered NRActive Video about health issues e.g. diet, exercise, and sleep.Random sequence generation NRAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out No (31.8%)Was ITT analysis NoSI (continuous): Beck Scale for Suicidal Ideation (BSSI)Longest follow-up: 1 month post-baselineHetrick et al. (2017) [123]AustraliaInclusion: Presented to school counselor with SIExclusion: Intellectual disability; psychotic symptoms; inability to speak EnglishRecruited Secondary schools (N = 18)Whole sampleN = 50Mean 14.7 (SD: 1.4)Gender: 18% maleTreatment groupN = 26Mean 14.8 (SD: 1.6)Gender: 19.3% maleControl groupN = 24Mean 14.5 (SD: 1.3)Gender: 16.7% maleOnline cognitive behavioral therapy (Reframe IT)Length: Eight self-directed modules over 10 weeksDeveloped study authorsDelivered self-directed, in the presence of school well-being staffTAU: contact with school wellbeing staff plus any outside mental health service provision normally available.Random sequence generation Online randomization program, stratified by schoolAllocation concealment The online program did not allow knowledge of treatment next to be allocated before the participant details were entered into the computerAscertainment of SH InterviewOutcome assessor NALess than 15% drop-out: No (28.6%)Was ITT analysis YesSI (continuous): SIQSA: a specifically designed questionnaire that asked participant whether they had attempted suicide since their last assessment, and if so, how many timesLongest follow-up: 3 months post-interventionHill & Pettit, (2016) [122]dUSAInclusion: Endorsed a perceived burdensomeness score of 17 or greater on the Interpersonal Needs Questionnaire Perceived Burdensomeness subscale (Van Orden et al., 2012)eExclusion: Current psychosocial treatment or use of psychoactive medications, unless on a stable dose for > 8 weeksRecruited Schools (N = NR) & public gathering placesWhole sampleN = 80Mean 16.9 (SD: 1.7; Range: 13–19)Gender: 31.2% maleTreatment groupN = 40Age/ NRControl groupN = 40Age/ NROnline cognitive behavioral therapy (LEAP: Learn, Explore, Assess you options, Plan)Length: Two modules delivered over two weeksDeveloped study authorsDelivered self-directedPlacebo: e-mail containing psychoeducational informationabout mental health & suicide, andresources for mental health treatment and suicide/crisis counseling.Random sequence generation Sequentially numbered envelopesAllocation concealment Sealed, opaque envelopesAscertainment of SH Self-report questionnaire.Outcome assessor NALess than 15% drop-out: Yes (13.8%)Was ITT analysis YesSI (continuous): BSSILongest follow-up: 2 months post-baselineHooven et al. (2012) [96]USAInclusion: Students who met criteria for suicide risk statusExclusion: NoneRecruited Secondary schools (N = 20)Whole sampleN = 615Mean 16.0 (SD: NR; Range: 14–19)Gender: 40% maleTreatment groupC-CAREN = 153Age/ NRP-CAREN = 155Age/ NRCombinedN = 164Age/ NRControl groupN = 143Age/ NRCombined intervention 1)Counselors Care, Assess, Respond and Empower (C-CARE)2)Parents Care, Assess, Respond and Empower (P-CARE)3)Combined C-CARE and P-CARELength: two 2-hour sessions over a 1-month periodDeveloped study authorsDelivered unclearPlacebo: brief screening interview.Random sequence generation NRAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out rate at post-intervention: UnclearWas ITT analysis UnclearSRB: High School Questionnaire: Profile of Experiences (HSQ)Longest follow-up: 15 months post-baselineNot included in MAKovac & Range, (2002) [114]USAInclusion: Students who screened positive for SRBExclusion: NoneRecruited University (N = 1)Whole sampleN = 121Mean 23.12 (SD: 5.44; Range: 18–42)Gender: 27.3% maleTreatment groupN = NRAge/ NRControl groupN = NRAge/ NRA writing interventionf to examine whether writing with ‘cognitive change’ reduced suicide risk when compared to writing just about suicidal experience and compared to controls.Group Wrote about being suicidal & were instructed to think about their thoughts and feelings at the time. Group Wrote about being suicidal but were asked to provide details about the event. Group Control.Length: four 20-min sessions delivered once a day for 4 daysDeveloped study authorsDelivered UnclearPlacebo: Wrote in detail about their bedroomRandom sequence generation NRAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out No (19.1%)Was ITT analysis NoSI (continuous): SIQLongest follow-up: 6 weeks post-interventionPistorello et al. (2012) [116]USAInclusion: Students seeking treatment from a University mental health service for SI, SA, or NSSIExclusion: psychosis, need for inpatient care, or prior DBT treatmentRecruited University (N = 1)Whole sampleN = 63Mean 20.9 (SD: 1.92)Gender: 19% maleTreatment groupN = 31Mean 20.4 (SD: 1.6)Gender: 22.6% maleControl groupN = 32Mean 21.3 (SD: 2.1) Gender: 15.6% maleA combination of individual and group dialectical behavioral therapy.Delivered Length: Comprised one 50-min individual psychotherapy session plus a 90-min group skills training session per week, over a 12-month period.Developed based on Linehan,(1993)gDelivered MH professionalsEnhanced TAU: included weekly individual & group therapy, weekly group supervision for therapists, & between-session consultation and family. Interventions as needed.Random sequence generation Computer generated adaptive randomizationAllocation concealment NRAscertainment of SH InterviewOutcome assessor NALess than 15% drop-out rate at post-intervention: No (22.2%)Was ITT analysis Yes. All participants with missing data were coded as unimproved.SI (continuous): Suicidal Behaviors Questionnaire (SBQ-23)SA: SBQ-32Longest follow-up: 18 months post-baselineRobinson W et al. (2016) [97]USAInclusion: Students who screened positive for SRBExclusion: NoneRecruited Secondary schools (N = 4)Whole sampleN = 330Mean NRRange: 14–17 + Gender: 40% maleTreatment NRControl NRGroup coping with stress 1) Identifying feelings of stress2) Reducing negative cognitions & increasing positive thoughts3) Identifying risk factors for stress4) Enhancing competencies for managing stress5) Planning for stress.Length: Fifteen 45-min sessionsDeveloped based on Robinson & Case (2003)h and adapted by study authorsDelivered MH professionalTAU: one-to-one sessions on stress management.Random sequence generation NRAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out Yes (0.6%)Was ITT analysis NRSI (categorical): Four suicidality screening items (not included in MA)Longest follow-up: Post-intervention onlyNot included in MATang et al. (2009) [98]TaiwanInclusion: Students with moderate–severe depression, SI, SA, moderate–severe anxiety, or significant hopelessness in previous 2 weeks.Exclusion: acute psychotic symptoms, act out lethal suicidal behaviors, lack proper care for suicide risk by their family, drug abuse, or serious medication conditionRecruited Secondary schools (N = 1)Whole sampleN = 73Mean NR (Range: 14–18)Treatment groupN = 35Mean 15.26 (SD: 1.7)Gender: 34% maleControl groupN = 38Mean 15.24 (SD: 1.65)Gender: 34% maleInterpersonal psychotherapyLength: Two sessions per week for 6 weeksDeveloped based on Mufson et al. (2004)i and adapted by study authorsDelivered School counselor & intern counseling psychotherapistsTAU: psycho-education and individual supportive counseling once or twice a week.Random sequence generation NRAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out Yes (0.0%)Was ITT analysis YesSI (continuous): BSSILongest follow-up: Post-intervention only

Multi-modal interventionsSchilling et al. (2014) [100]USAInclusion: Middle school studentsExclusion: NoneRecruited Middle schools (N = 8)Whole sampleN = 470Age: NRGender: 47.4% maleTreatment NRControl NRSuicide-specific psycho-education (plus screening).Signs of Suicide (SOS). Video & discussion guide depicting signs of suicidality & depression and recommended ways to respond. Also included screening to identify students at risk.Length: Video = 17 minDeveloped Screening for Mental Health Inc.Delivered TeachersAttended class as usual & received the program after the study periodRandom sequence generation Cluster simple randomization. However, 2 schools allocated to control crossed over into the interventionAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out UnclearWas ITT analysis NoSRB: Centers for Disease Control and Prevention's (CDC) Youth Risk Behavior Survey (YRBS)Longest follow-up: 3-months post-interventionNot included in MASchilling et al. (2016) [99]USAInclusion: ninth-grade studentsExclusion: NoneRecruited Secondary schools (N = 16)Whole sampleN = 1272Mean NR (Range14–15)Gender: 58.3% maleTreatment groupN = 719Age: NRGender: 55.8%ControlN = 553Age: NRGender: 61.6% maleSuicide-specific psycho-education (plus screening).Signs of Suicide (SOS). As above.Waitlist controlRandom sequence generation Cluster simple randomization.Allocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out UnclearWas ITT analysis NoSI (dichotomous): CDC YRBSLongest follow-up: Post-intervention only

Multiple interventionsWasserman et al. (2015) [101]Multi-site: 10 European countriesInclusion: all students in participating classroomsExclusion: None (although students who reported suicide attempts ever, or severe suicidal ideation in the past 2 weeks before the baseline assessment, and those with missing data regarding these two variables were excluded from the final analysis)Recruited Secondary schools (N = 168)Whole sampleN = 11,110Mean 14.8 (SD:0·82 Range: 14–16)Gender: NRTreatment group 1N = 2692Mean 14.8 (SD: 0.82)Gender: 37% maleTreatment group 2N = 2721Mean 14.8 (SD: 0.85)Gender: 40% maleTreatment group 3N = 2764Mean 14.8 (SD: 0.8)Gender: 42% maleControl groupN = 2933Mean 14.78 (SD: 0.89)Gender: 44% malePsycho-educational (universal) componentYouth Aware of Mental Health Programme (YAM), a universal intervention that aims to raise awareness of risk & protective factors associated with suicide, including knowledge of depression/anxiety and to enhance skills to manage stress, adverse life events & suicidal behaviorsLength: 3 h role play session plus 2 × 1 h lecturesDeveloped study authorsGatekeeper training (selective) componentQuestion, Persuade, and Refer (QPR), a gatekeeper training module targeting teachers and other school personnel.Length: NRDeveloped Tompkins et al. (2010)jScreening (selective) componentScreening by health professionals (ProfScreen) with referral of at-risk pupils.Length: NADeveloped study authorsDelivered Trained instructorsActive The control group was exposed to the same 6 educational posters as the YAM group. These included information about local health-care providers.Random sequence generation Cluster stratified randomization using a random numbers tableAllocation concealment NRAscertainment of SH Self-reportOutcome assessor NALess than 15% drop-out No (26.3%)Was ITT analysis NoSI (dichotomous): single item from five item Paykel Hierarchical Suicidal LadderSA (dichotomous): single item from five item Paykel Hierarchical Suicidal LadderLongest follow-up:12 months (not specified if post-test or post-intervention)Notes: ED = Emergency Department; ITT = intention-to-treat; IQR = Interquartile Range; MA = meta-analysis; MH = mental health; NA = not applicable; NR = not reported; TAU = treatment as usual; SA = suicide attempt; SD = standard deviation; SH = self-harm; SI = suicidal ideation; SRB = suicide-related behavior.aRoss CP. School and Education for life and death. In RFW Diekstra & K Hawton (Eds.), Suicide in adolescence. Dordrecht: Martinus Nijhoff, 1987.bExcluded secondary Randell BP et al. Immediate post-intervention effects of two brief youth suicide prevention interventions. Suicide Life Threat Behav 2001; 31(1): 41–61.cD'Zurilla TJ, Nezu AM. Development and preliminary evaluation of the Social Problem-Solving Inventory. Psychol Asses 1990; 156–163.dNote: This study recruited participants from both schools and the community.eVan Orden KA, et al. Thwarted belongingness and perceived construct validity and psychometric properties of the Interpersonal Needs Questionnaire. Psychol Assess 2012; 197–215.fClassified as BCI in the meta-analysisgLinehan MM. Skills training manual for treating borderline personality disorder. New York: Guilford Press, 1993.hRobinson WL, Case MH. Leader manual for the Down with Drama course. Unpublished Manual. DePaul University; Chicago: Illinois: 1995.iMufson L, et al. Effectiveness Transporting interpersonal psychotherapy for depressed adolescents (IPT-A) from the lab to school-based health clinics. J Consult Clin Psychol 2004; 251–261.jTompkins TL, et al. Does a gatekeeper suicide prevention program work in a school setting? Evaluating training outcome and moderators of effectiveness. Suicide Life Threat Behav 2010; 506–15.Table 4Study Non-randomized controlled trials conducted in educational or workplace settings (N = 16).Table 4Study; countryStudy design; level of evidenceTarget populationParticipantsIntervention descriptionComparison conditionRisk of biasSuicide related outcome(s) assessed; Longest follow-upResultsInterpretationUniversal interventionsBailey et al. (2017) [110]AustraliaStudy Pre-test/post-test case seriesLevel of IVInclusion: year 11 and 12 students at participating schoolsExclusion: NoneRecruited Secondary schools (N = 3)Whole N = 129Mean 16.7 (range 16–18)Gender: 53.5% maleEducationalsafeTALKLength: One 3-hour sessionDeveloped LivingWorksDelivered Trained instructorsNAAdequately NoOutcome assessor NALess than 15% drop-out No (25.9%)Use of statistical testing to measure change at from pre-test to post-test: YesSI: Single item asking participants to indicate whether or not they were experiencing current suicidal thoughts.Longest follow-up: 1 month post-interventionSI: NRIn comparisonwith Time 1 (the reference category), individuals atTime 2 had 0.53 times the odds of experiencing suicidal thoughts (95% CI = 0.20–1.36), and at Time 3 had 0.30 times the odds (95% CI = 0.10–0.91).King et al. (2011) [102]USAStudy Pre-test/post-test case seriesLevel of IVInclusion: Students at participating schoolsExclusion: NoneRecruited Secondary schools(N participating = NR, but the program was implemented in 24 schools).Whole N = 1030Mean 14.1 (SD: 0.79; range 14–18)Gender: 43.9% maleEducationalSurviving the Teens® Suicide Prevention andDepression Awareness Program.Length: Four 50-min sessionsDeveloped Study authorsDelivered MH professionalsNAAdequately No power calculations provided. However, likely to be adequately powered for SI but not SA.Outcome assessor NALess than 15% drop-out No (59.6%)Use of statistical testing to measure change at from pre-test to post-test: YesSI: Single item asking participants to indicate whether or not they were currently seriously considering attempting suicideLongest follow-up: 3 months post-interventionSI: Post-testYes = 2.9% (n = 26)Follow-upYes = 1.5% (n = 6)There was no significant change in the number of students seriously considering suicide at post-intervention from pre-intervention (χ2 = 0.837, p = 0.360). At 3-month follow-up, students were significantly less likely than at pre-test to be currently considering suicide (p = 0.035).LaFromboise & Howard-Pitney, (1994) [93]USAStudy Non-randomized experimental trialLevel of III-2Inclusion: Students attending a Zuni secondary schoolExclusion: NoneRecruited Secondary school(N = 1)Whole N = 83Mean 15.6 SD/Range: NRGender: 41% maleTreatment NRControl NREducationalThe Zuni Life Skills Development Curriculum.Units information about suicide; suicide intervention skills; communication skills; coping with oppression; anger & stress management and goal setting.Length: Six units delivered across 28 lessonsDeveloped Study authorsDelivered TeachersNRIntervention Study authorsAdequately UnclearOutcome assessor NA Less than 15% drop-out No (25.3%)Use of statistical testing to measure change at from pre-test to post-test: YesSI: Suicide Ideation subscale of the Suicide Probability Scale (SPS)Longest follow-up: Post-intervention onlySI: Intervention mean (SD): 13.4 (NR)Control mean (SD): 16.8 (NR)No between-group statistical analysis completed.LaFramboise & Howard-Pitney, (1995) [94]USAStudy Non-randomized experimental trialLevel of III-2Inclusion: Freshman and junior students taking language arts classes at a Zuni secondary schoolExclusion: NoneRecruited Secondary school (N = 1)Whole N = 128Mean 15.9 (Range: 14–19)Gender: 36% maleTreatment N = 69Age/ NRControl N = 59Age/ NREducationalThe Zuni Life Skills Development Curriculum.Units: building self-esteem; identifying emotions & stress; communication & problem-solving skills; recognizing & eliminating self-destructivebehavior; suicide information; suicideintervention training; goal settingLength: Seven units delivered 3 times a week over approx. 30 weeksDeveloped Study authorsDelivered TeachersNo interventionAdequately NoOutcome assessor NALess than 15% drop-out No (23.4%)Use of statistical testing to measure change at from pre-test to post-test: YesSRB: SPSLongest follow-up: 8 months post-baselineSRB: Intervention mean (SD): 54.3 (SD: 11.6)Control mean (SD): 58.9 (SD: 13.0)The treatment group was less suicidal after taking part in the curriculum than the control group, t[61] = 1.45, p < 0.07.Vieland et al. (1991) [103]USAStudy Non-randomized experimental trialLevel of III-2Inclusion: Ninth grade students from participating schoolsExclusion: Schools excluded if they had ever received a suicide prevention programRecruited Secondary schools(N = 4)Whole N = 381Mean 15.8Gender: NRTreatment N = 174Mean 15.8(SD: 0.64)Gender: 45% maleControl N = 207Mean 15.8(SD: 0.59)Gender: 51% maleEducationalIn-class presentation. Emphasized support networks in alleviating stress, confronting one's peers, and community resources.Length: 1.5 hDeveloped UnclearDelivered TeachersNo interventionAdequately NoOutcome assessor NALess than 15% drop-out UnclearUse of statistical testing to measure change at from pre-test to post-test: NoSA: Single item asking participants to indicate whether or not they had made a first suicide attemptLongest follow-up: 18 months post-baselineSA: Intervention: Yes = 2.5%Control: Yes = 2.7%There was no evidence that the program had an effect on suicide attempt rates.

Selective interventionsHazell & Lewin (1993) [104]AustraliaStudy Post-test case seriesLevel of IVInclusion: Students who had been exposed to the suicide of a peerExclusion: NoneRecruited Secondary schools(N = 2)Whole N = 126Mean age/ NRTreatment N = 63Age/ NRControl N = 63Age/ NRTherapeuticOne session of group counseling provided at school within 7 days of a student suicide. Following the session, school staff were debriefed & arrangements made to follow-up high risk students.Length: 90 minDeveloped Study authorsDelivered MH professionalsUnclearAdequately NROutcome assessor NALess than 15% drop-out UnclearUse of statistical testing to measure change at from pre-test to post-test: YesSA: Hospitalization for SA assessed using Youth Self Report(YSR) version of the Child BehaviorChecklist (CBCL)SH: Incidence of current suicidal behavior - YSR CBCLSI: % of group currently experiencing suicidal ideation – YSR CBCLLongest follow-up: Post-intervention onlySA: Intervention: 1.6%Control: 0.0%SH: Intervention: 21.0%Control: 19.0%SI: Intervention: 14.5%Control 19.0%There were no differences between groups on SA, SH or SI as assessed by Pearson X2McDaniel et al. (1990) [121]USAStudy Interrupted time series with a control groupLevel of III-2Inclusion: US Navy instructorsExclusion: NoneRecruited Navy training command (N = 1)NRTraining sessions for instructors in US Navy training command. Focused on how instructors can identify signs of distress and risk in their students, how to intervene and how to get help.Length: 3 × 1 hDeveloped UnclearDelivered MH professionals“Operational command” - less than 10 miles away from training command and about the same size but no training.Adequately NROutcome assessor NALess than 15% drop-out UnclearUse of statistical testing to measure change at from pre-test to post-test: YesSA: Average monthly rate of SA (obtained from official sources)Longest follow-up: NASA: Post-testIntervention 9.4Control 1.8There was a declining trend in the suicide attempt rate in the intervention group. At post-test, the average monthly suicide attempt rate was significantly higher in the intervention group, p < 0.001.

Indicated interventionsBiddle et al. (2014) [105]USAStudy Post-test case seriesLevel of IVInclusion: Students demonstrating SRBExclusion: NARecruited Secondary schools(N = 619)N = 18,445Mean NR(Range: 13–21)Gender: NRTherapeuticStudent Assistance Program (SAP):* Identify individual student problems & recommend interventions. Participants are students referred to the SAP who accessed the recommended services.Length: NADeveloped Commonwealth Student Assistance Program Interagency Committee, Pennsylvania.Delivered Trained school staffNo interventionAdequately YesOutcome assessor NALess than 15% drop-out UnclearUse of statistical testing to measure change at from pre-test to post-test: UnclearSuicide: Number of suicides and suicide rate per 100,000 studentsLongest follow-up: NASuicide: Post-testIntervention N (rate): 9 (65.2)Control N (rate): 6 (129.25)The difference in suicide rates was not statistically significant.Eggert et al. (1995) [106]; (1999)a[36],USAStudy Post-test case seriesLevel of IVInclusion: Students SA; SI; moderate-serious depression;specific levels of alcohol or other drug use, polyuse, or drug use control problemsExclusion: NoneRecruited Secondary schools(N = 5)Whole N = 105Mean age/ NRPGC I N = 36Mean 16.19 (SD: 0.92)Gender: 41.7% malePGC II group N = 34Mean 15.82 (SD: 1.11)Gender: 37.1% maleControl: N = 35Mean 15.57 (SD: 1.01)Gender: 45.7% malePsycho-educationPersonal growth classes (PGCs): Incorporated [1] group work; [2] weekly monitoring of activities targeting changes in mood management, school performance and attendance, and drug involvement; and [3] life skills training in self-esteem enhancement, decision making, personal control (skills training in anger, depression, and stress management), and interpersonal communication.Length: (PGC I): One semester - 5 months or 90 class days;(PGC-II): Two semesters − 10 months or 180 class days.Developed Study authorsDelivered Trained school staffEnhanced TAU: Assessed for suicide ‘potential’.Adequately NROutcome assessor NALess than 15% drop-out UnclearUse of statistical testing to measure change at from pre-test to post-test: YesSRB: The Brief Suicide Risk Behavior Scale; A 5-item scale measuring the frequency of suicide thoughts, direct and indirect suicide threats, and suicide attemptsLongest follow-up: 10 months post-interventionSRB: Post-testPGC1 mean (SD): 0.27 (0.55)PGC2 mean (SD): 0.66 (0.85)Control mean (SD): 0.55 (0.65)Follow-upPGC1 mean (SD): 0.56 (0.93)PGC2 mean (SD): 0.66 (0.79)Control mean (SD): 0.23 (0.37)There was no significant difference in suicide risk behaviors between the groups. There was a significant decline in suicide risk behaviors for all three groups (F Linear [1], [102] = 104.14, p < 0.001) revealed a significant decline for all three groups.Joffe (2008) [118]USAStudy Interrupted time series with a control groupLevel of III-2Inclusion: Students with a SA or suicide ‘threat’Exclusion: NARecruited University(N = 1)Student populationTreatment 1980–1983: 139,384 1984–1990: 249,812Control 1980–1983: 1,244,4691984–1990: 1,807,968PolicyImplementation of a policy requiring any student who made a suicide threat or attempt to receive 4 individual sessions of professional assessment, the first which occurred within a week of the incident.Length: NRDeveloped Counseling Center, University of IllinoisDelivered MH professionalsData collected from 11 other universitiesAdequately NROutcome assessor NALess than 15% drop-out Not ReportedUse of statistical testing to measure change at from pre-test to post-test: YesSuicide: Deaths by suicide per 100,000 enrolled students per yearLongest follow-up: NASuicide: Post-testIntervention 2.0Control 8.68The treatment group had a 74.7% reduction in the suicide rate, compared to an increasing suicide rate in the comparison group, z score = 5.90, p < 0.05Lerner & Clum (1990) [117]USAStudy Non-randomized, experimental trialLevel of III-2Inclusion: Students with SIExclusion: Psychosis, substance abuseRecruited University(N = 1)Whole sampleN = 18Mean 19.17 (SD: 1.38; Range: 18–24)Gender: 22% maleTreatment groupN = 9Mean 18.78 (SD: 0.83; Range: NR)Gender: 11% maleControl groupN = 9Mean 19.56 (SD: 1.74)Gender: 33% maleTherapeuticgroup problem solving therapyLength: 10 sessions over 5–7 weeksDeveloped Based on D'Zurilla and Goldfried (1971)bDelivered MH professionalActive empathetic listening, sharing experiences with the group.Adequately NoOutcome assessor NALess than 15% drop-out Yes (0.0%)Use of statistical testing to measure change at from pre-test to post-test: YesSI: Modified Scale for Suicidal Ideation (MSSI)Longest follow-up: 3 months post-interventionSI: Post-testIntervention mean (SD): 5.8 (7.0)Control mean (SD): 5.3 (9.2)3-month follow-upIntervention mean (SD): 4.7 (3.4)Control mean (SD): 10.6 (8.8)There was no significant difference in suicidal ideation between the groups at both time points (T2: F value < 1; T3: F value = 1.87)Robinson J et al. (2016)c[112],AustraliaStudy Pre-test/post-test case seriesLevel of IVInclusion: Students who presented to the school counselor with SI in the past monthExclusion: ID, psychosis, inability to speak EnglishRecruited Secondary schools(N = 11)Whole N = 32Mean 15.6 (Range: 14–17)Gender: 12.5% maleTherapeuticReframe-IT.Individual online suicide-specific CBT: eight 20-min modules incorporating standard CBT approaches commonly used with young people.Length: eight 20-min modulesDeveloped Study authorsDelivered self-directedNAAdequately NoOutcome assessor NALess than 15% drop-out No (38.2%)Use of statistical testing to measure change at from pre-test to post-test: YesSI: Suicidal Ideation Questionnaire (SIQ)Longest follow-up: Post-intervention onlySI: Pre-testMean (SD): 3.2 (1.6)Post-testMean (SD): 1.5 (1.3)There was a statistically significant decrease in SI from per to post-test, with a moderate effect size, t = 6.2; p < 0.0005

Multi-modal interventionsAseltine et al. (2007)d[107],USAStudy Pseudo-RCTLevel of III-1Inclusion: Students at participating schoolsExclusion: NoneRecruited Secondary schools (N = 9)Whole sampleN = 4133Mean age/ NRGender: 50.0% maleTreatment 2039Control 2094Psycho-education & screeningSigns of Suicide (SOS).Universal educational * Video & discussion guide depicting signs of suicidality & depression and recommended ways to respond. Selective * Screening to identify students at risk.Length: Video = 17 minDeveloped Screening for Mental Health Inc.Delivered NRAttended class as usual & received the program after the study periodAdequately No power calculations provided. However, likely to be adequately powered for SI but not SA.Outcome assessor NALess than 15% drop-out UnclearUse of statistical testing to measure change at from pre-test to post-test: NoSA: Item from the Youth Risk Behavior Survey (YRBS): During the past 3 months did you actually attempt suicide?SI: Item from the YRBS: During the past 3 months did you ever seriously consider attempting suicide?Longest follow-up: 3 months post-interventionSA: Post-test% answered “Yes”Intervention: 3.0%Control: 4.6%SI: Post-test% answered “Yes”Intervention: 10.1%Control: 11.5%Participants in the treatmentgroup were 40% less likely to report a SA in the past 3 months compared with participantsin the control group, beta = − 0.47 (SE 0.16), p = 0.0075 (OR = 47%)There was no significant effect of the SOS program on SI, beta = − 0.53 (SE = 1.01), p > 0.05Shelef et al. (2016) [120]IsraelStudy Interrupted time series with a control groupLevel of III-2Inclusion: Active duty mandatory service military personnel who served between 1992 and 2012Exclusion: subsection of the populationthat did not represent the regular mandatory service soldiersRecruited Israeli Defense ForceWhole N = 1,171,359Mean 19.0 (Range: 17–24)Gender: 53.4% maleTreatment N = 405,252Mean 19.0Gender: 55.2% maleControl N = 766,107Mean 19.0Gender: 15.4% maleMultipleIsraeli Defense Force Suicide Prevention Program. Includes: means restriction, improved screening & management of suicidal soldiers, psycho-education and gatekeeper training.Length: NADeveloped Based on Knox et al. (2003)eDelivered NRCohort inducted into the IDF prior to the implementation of the intervention (1992–2005)Adequately YesOutcome assessor NALess than 15% drop-out NRUse of statistical testing to measure change at from pre-test to post-test: YesSuicide: Total number of suicides & average number per yearLongest follow-up: NASuicide: Pre-intervention (2006–2012): N = 344; 24.6 per yearPost-intervention (1992–2005): N = 89; 12.7 per yearTrend analysis showed lower suicide rates in the cohort after intervention, Hazard ratio = 0.48 (95%CI: 0.37–0.60)Silverstone et al. (2015) [108]; (2017) [37]CanadaStudy Pre-test/post-test case seriesLevel of IVInclusion: All secondary school students, plus targeted intervention for students with SI (with or without SA)Exclusion: NoneRecruited Secondary schools(N = 5)N = 3244Mean NR (Range: 10–19)Gender: 51.7% maleTherapeutic & screeningEmpowering a Multi-modal Pathway Toward Healthy Youth (EMPATHY): Universal CBT for all students in years 7 and 8; screening for all students; rapid intervention, guided online CBT for those identified as being at-risk.Length: Universal CBT = 8–16 sessions; online CBT = NRDeveloped Study authorsDelivered MH professionalsNAAdequately YesOutcome assessor NALess than 15% drop-out No (24.2%)Use of statistical testing to measure change at from pre-test to post-test: YesSI: N at “High risk” (“thought you were better off dead” more than half the days in past 2 weeks) or “medium risk” (“thought you were better off dead” several days in past 2 weeks) of suicideLongest follow-up: 15 months post-baselineSI: 12-week follow-upHigh risk N = 30Medium risk N = 19Actively suicidal N = 4915-month follow-upHigh risk N = 16Medium risk N = 21Actively suicidal N = 37Less students were at “high” or “medium” risk of suicide at follow-up compared to baseline (significance testing not reported).At 15-month follow-up, significantly less people were “actively suicidal” (high or medium risk) than at baseline, p < 0.001Zenere & Lazarus, (1997) [109]USAStudy Interrupted time series without a control groupLevel of III-3Inclusion: All public secondary school students in Miami, FloridaExclusion: NARecruited Secondary schools(N = 300)NRMultipleSuicide Prevention and School Crisis Management Program: Comprising psycho-education, postvention, school-based crisis teams, staff training, crisis hotline.Length: NADeveloped Dade County Public Schools Department, Florida.Delivered MH professionals & teachers.Cohort of students at beginning of implementation of the SPSCMP (1989–1990)Adequately No power calculations provided. However, likely to be adequately powered for SI but not SA.Outcome assessor NALess than 15% drop-out NRUse of statistical testing to measure change at from pre-test to post-test: NoSI: Number of suicidal ideations, obtained via hotline reportsSA: number and rate of suicide attempts, obtained via hotline reportsLongest follow-up: NASI: Pre-test (1989–1990)N = 641Post-test (1993–1994)N = 640SA: Pre-testN = 243; 87/100,000Post-testN = 95; 31/100,000The number of suicidal ideations among students fluctuated during the data collection period, initially showing a decrease in activity before returning to previous levels.The rate of suicide attempts decreasedNotes: ED = Emergency Department; ID = Intellectual Disability; ITT = intention-to-treat; IQR = Interquartile Range; MH = mental health; NA = not applicable; NR = not reported; TAU = treatment as usual; SA = suicide attempt; SD = standard deviation; SH = self-harm; SI = suicidal ideation; SRB = suicide-related behavior.a1999 is a correction; excluded secondary Thompson EA, et al. Mediating effects of an indicated prevention program for reducing youth depression and suicide risk behaviors. Suicide Life Threat Behav 2000; 30(3): 252–71.bD'Zurilla T, Goldfried M. Problem solving and behavior modification. J Abnorm Psychol 1971; 107–126.cExcluded secondary Robinson J, et al. The safety and acceptability of delivering an online intervention to secondary students at risk of findings from a pilot study. Early Interv Psychiatry 2015; 9(6): 498–506.; Hetrick S, et al. Does cognitive behavioural therapy have a role in improving problem solving and coping in adolescents with suicidal ideation? Cognitive Behaviour Therapist 2014; 7.dExcluded secondary Aseltine RH, DeMartino R, An Outcome Evaluation of the SOS Suicide Prevention Program. American Journal of Public Health 2004; 94(3): 446–451.eKnox KL, et al. Risk of suicide and related adverse outcomes after exposure to a suicide prevention programme in the US Air Force: cohort study. BMJ 2003; 327(7428):1376.Table 5Interrupted time series and ecological studies in community settings (N = 15).Table 5Study; countryStudy design; level of evidenceTarget region/population; comparisonIntervention descriptionTime periodRisk of biasOutcome/data sourceRates per 100,000InterpretationUniversal: means restrictionBeautrais et al. (2006) [125]New ZealandStudy Interrupted time series without a control groupLevel of III-3Target region/ NAComparison: NoneFirearms legislation introduced in 1992 mandating license to own a firearm.1985–1992: pre-legislation;1993–1996: implementation;1997–2002: post-implementation.Were data collected at multiple time points?a YesWas the intervention likely to affect data collection? No: Data collection from official mortality data at a national levelSuicide: Mean annual age-specific suicide rates by all methods and by firearm for persons aged 15–24 years, obtained through New Zealand Health InformationService (NZHIS)Suicide: All: UnclearFirearm: UnclearThere was a 66% decrease in the mean annual rate of firearm-related suicide (B = − 1.09; SE = 0.24; p < 0.001).There was a decrease in the fraction of all suicides accounted for by firearm-related suicides (p < 0.0001). There was no significant decrease in overall rates of suicide (b = 0.08; SE = 0.10; p = 0.39).Caron (2004) [126]CanadaStudy Interrupted time series without a control groupLevel of III-3Target region/ Northern QuebecComparison: NoneFirearms legislation introduced in 1992 mandating firearm owners to safely store their firearms.1986–1991: pre-legislation;1992–1996: post-legislationWere data collected at multiple time points? YesWas the intervention likely to affect data collection? No: Data collection from official mortality datasetSuicide: Age-specific suicide rates by all methods and by firearm for under 25 age group obtained through the Quebec Coroner's office.Suicide: All: NRFirearm: NRThere was a 38% decrease in firearm suicides (significance = NR).There was a 69% increase in the overall suicide rate (X2 = 22.09, df = 1, p < 0.001).Cheung and Dewa (2005) [128]CanadaStudy Interrupted time series without a control groupLevel of III-3Target region/ NAComparison: noneRestrictive firearms regulations - Bill C-17 enacted in 1991.1979: pre-implementation1999: post-implementationWere data collected at multiple time points? YesWas the intervention likely to affect data collection? No: data collection from official mortality dataset.Suicide: Age-specific suicide rates for youth between 15 and 19 years by firearm, overdose, hanging, and total, and percentage of suicides by each particular method, obtained from data collected by the Coroner's office.Suicide: All: UnclearFirearm: Unclear1999: 3.0Overdose: 1.21999: 0.2Hanging: 2.61999: 7.8The findings suggest a substantial decrease in firearm-related suicides but no decrease in the overall suicide rate (significance = NR).Leenaars & Lester (1997) [131]CanadaStudy Interrupted time series without a control groupLevel of III-3Target region/ NAComparison: NoneGun control legislation introduced in 1977 (Bill C-51).1969–1976: pre-legislation1978–1985: post-legislationWere data collected at multiple time points? YesWas the intervention likely to affect data collection? No: data collection from official sources.Suicide: Suicides rates by firearm and by all methods, and percentage of total suicide rate by firearm, in persons aged 15–24, obtained from Statistics Canada and supplemented by personal communications.Suicide: All: Pre-legislation: 12.57Post-legislation: 16.11Firearm: Pre-legislation: 5.89Post-legislation: 7.12There was a significant increase in the mean firearm suicide rate and mean total suicide rate from pre-legislation to post-legislation (p < 0.05).There was no statistically significant change in the percentage of all suicides that were by firearm.Lubin et al. (2010) [132]IsraelStudy Interrupted time series without a control groupLevel of III-3Target region/ Defense Force personnelComparison: NoneRule prohibiting soldiers from taking home service weapons on the weekend.T1: 2003–2005T2: 2007–2008Were data collected at multiple time points? NoWas the intervention likely to affect data collection? No: Israeli Defense Force suicide data.Suicide: Average number of suicide deaths per year; firearm suicides on weekends; firearm suicides on weekdays in soldiers aged 18–21: data source not specified.Suicide: All: NRFirearm suicides on NRFirearm suicides on NRFollowing policy change, suicide rates decreased significantly by 40% (t = 3.35, p = 0.04). Most of this decrease was due to decrease in suicide using firearms over the weekend (t = 17.44, p < 0.001). There was no significant change in rates of suicide on weekdaysNiederkrotenthaler et al. (2009) [135]AustriaStudy Interrupted time series without a control groupLevel of III-3Target region/ NAComparison: None1997 revision of firearm laws to harmonize with EU regulationsT period 1–1986-1987T period 2 - 1987–2006Were data collected at multiple time points? YesWas the intervention likely to affect data collection? No: National mortality data.Suicide: Suicide rates by firearm and all methods in 10–19 year-olds, obtained from Statistics Austria.Suicide: All: NRFirearm: UnclearThere was a temporary increase in firearm suicides, followed by a continuous decrease (adjusted − 0.20 95% CI − 0.33 to − 0.07; p = 0.003). On the whole, firearm suicide rates after the firearm legislation reform were significantly lower than before the reform. The adjusted model showed no changes in total suicide rates associated with the reform (adjusted 0.017 95%CI 0.04–0.074; p = 0.533).Wheeler et al. (2009) [137]Multi-national (23 Countries of 35 with available suicide data from the WHO's Mortality Stratum A).Study Interrupted time series without a control groupLevel of III-3Target region/ NAComparison: None“Regulatory action” to restrict use of SSRIsPre-intervention: 1990–2003Post-intervention: 2004–2006Were data collected at multiple time points? YesWas the intervention likely to affect data collection? No: National mortality data & Hospital admissions data.Suicide: Suicide rates in 10–14 and 15–19 year-olds, obtained from WHO mortality database.Suicide: NRThere was no evidence for an overall effect on the incidence of suicide of regulatory action regarding SSRIs for 15–19 year-olds (p = 0.95) or 10–14 year-olds (p = 0.97).Wheeler et al. (2008)b[136],UKStudy Interrupted time series without a control groupLevel of III-3Target region/ Young people treated with SSRIsComparison: NoneRestriction of SSRIsSuicide deathsPeriod 1–1993-2003Period 2–2003-2005Self-harmPeriod 1 1999–2003Period 2–2003-2005Were data collected at multiple time points? YesWas the intervention likely to affect data collection? No: National mortality data & Hospital admissions data.Suicide: Mortality rates due to intentional self-harm or undetermined intent in 12–17 year-olds, obtained from Office for National Statistics.SA/SH: Hospital admissions per year due to intentional self-harm or undetermined intent in 12–17 year olds, obtained from the Department of Health Hospital Episode StatisticsSuicide: UnclearAdmissions for SA/SH: Males1999: ~ 1202005: ~ 120Females1999: 3672005: 525There was no statistical evidence of changes in trends in suicide rates between 1993 and 2005.The rate of hospital admissions remained relatively stable in males and steadily increased in females.

Multi-modalAhmadi & Ytterstad (2007) [124]IranStudy Interrupted time series with a control groupLevel of III-2Target region/ Young women and low SES in 2 citiesComparison: Sarpolzahab hospital (reference group)Multi-modal: mix of passive and active strategies (not described). Key feature was psycho-education via videosPre-intervention - 1999–2000Intervention - 2000–2003Were data collected at multiple time points? NoWas the intervention likely to affect data collection? Yes: Possible that those involved in data collection were not blinded to the intervention (suicide attempts).SH: N (%) of total self-inflected burn cases who was admitted in Gilangharb and Sarpolzahab hospitals during the baseline year to the study, during the study period, and the last year of the study period in persons aged 0–20 years.SH: NRNo statistical analyses were performed on rates of self-immolation in youth.Center for Disease Control (1998) [127]USAStudy Interrupted time series without a control groupLevel of III-3Target region/ Western Athabaskan tribe in rural New Mexico, USAComparison: NoneMulti-modal: gatekeeper training, outreach to families, immediate response and follow up for reported at-risk youth, community psychoeducation, and screening in services.1988–1989: pre-implementation;1990–1999: post-implementationWere data collected at multiple time points? YesWas the intervention likely to affect data collection? It is possible that those involved in data collection were not blinded to the intervention (suicide attempts). This was a not a problem with suicide deaths as this was obtained from official sources.SRB: Rates of suicide acts for persons aged 15–19 (included completions and attempts) obtained via a surveillance form.SRB: 1988–1989: 59.81990–1991: 8.91992–1993: 9.21994–1995: 17.61996–1999: 10.9Although rates varied after implementation of the program, they remained substantially lower than before the program was initiated.Cwik et al. (2016) [129]USAStudy Interrupted time series without a control groupLevel of III-3Target region/ Apache IndiansComparison: NoneMulti-modal: implemented in 2006, included psychoeducation for students, gatekeeper training, and indicated interventions for suicidal young people.2001–2006: pre-implementation2007–2012: post-implementationWere data collected at multiple time points? YesWas the intervention likely to affect data collection? Yes: it is possible that those involved in data collection were not blinded to the intervention (suicide attempts).Suicide: Suicide rates for persons aged 10–24 years, obtained via The Celebrating Life surveillance system (established by tribal resolution in 2001).Suicide: Pre-test: 10–14 years: 17.115–19 years: 23.620–24 years: 151.9Post-test: 10–14 years: 23.615–19 years: 101.920–24 years: 96.0The suicide rate increased by 38% in 10–14 year-olds, and decreased by 5.5% in 15–19 year-olds and 36.8% in 20–24 year-olds.Hacker et al. (2008) [130]USAStudy Interrupted time series without a control groupLevel of III-3Target region/ Somerville, MA, USAComparison: MassachusettsMulti-modal: implemented between 2003 and 2005, included local trauma response network, community wide vigil, school based counseling, hospital beds made available, outreach to suicide survivors to offer services, youth leadership programs, media reporting guidelines, community-wide education.1994–2003: pre-intervention period.2003–2005: Intervention period.2005 post-intervention.Were data collected at multiple time points? YesWas the intervention likely to affect data collection? No: data collection from official sources.Suicide: Data on suicide rates for 10–24 year-olds obtained via death certificate data (examined from 2001 to 2007, and then from 1994 for comparison), mortality data from Massachusetts Department of Public Health for (1994–2005).SA/SH: Data on suicide attempts for 10–24 year-olds obtained via self-inflicted injury data from Massachusetts Department of Public Health for (1994–2005), hospital discharge data (1996–2006), 911 dispatch call data (2004 onwards), teen health survey conducted in Somerville High School.SI: Teen health surveySuicide: 1994–1999: Somerville: 6.042000–2005: Somerville: 9.77Massachusetts: 4.27SA/SH: 2005Somerville: 47.3Massachusetts: 73.72006Somerville: 53.2Massachusetts: 74.8Overall the data indicates a decrease in the rate of suicide and suicide attempts (significance = NR).May et al. (2005) [134]USAStudy Interrupted time series without a control groupLevel of III-3Target region/ Western Athabaskan Tribal Nation. New Mexico, USAComparison: NoneMulti-modal: Surveillance, screening/clinical interventions with extensive outreach in multiple settings, school-based prevention programs, community education for adults and youths, training of ‘natural helpers.Baseline - 1988–1989; then two yearly numbers and yearly averages until 2002Were data collected at multiple time points? YesWas the intervention likely to affect data collection? Unclear: program providers also main data collectors for non-fatal behaviors, participants may avoid reporting.SRB: Number of self-harm incidents (attempts and gestures combined) in 11 to 24 year-olds obtained from staff case conference notes and Indian Health Service records.SRB: NRThere was a significant decline in the number of combined gestures and attempts in 19–24 year-olds (coeff = − 765, p = 0.001) and 11 to 18 year-olds (coeff = − 0.517, p = 0.048).

Multiple interventionsGarraza et al. (2015) [139]; Walrath et al. (2015) [38]USAStudy EcologicalLevel of III-2Target region/ 466 counties, USAComparison: 1161 counties not exposed to suicide prevention effortsMultiple: Activities funded by the Garrett Lee Smith (GLS) Memorial Suicide Prevention Program, implemented between 2006 and 2009. Includes gatekeeper training, psychoeducation programs, screening, improved community partnerships and linkages to service, postvention programs, and crisis hotlines.At least 1 NSDUHrespondent between2008 and 2011, suicide mortality between 2007 and 2010Were data collected at multiple time points? NoWas the intervention likely to affect data collection? No: Data collection from official sources.SA: Suicide attempt rates for each county following the implementation of the GLS program for the population that was approximately 16 to 23 years of age during implementation, obtained via self-report from the NSDUH between 2008 and 2011Suicide: Suicide rates for persons aged 10–24 years between 2007 and 2010, obtained from the National Vital Statistics System.SA: NRSuicide: NRSuicide Counties implementing GLS program activities had significantly lower suicide attempt rates among youths 16 to 23 years of age in the year following implementation of the GLS program than did similar counties that did not implement GLS program activities (4.9 fewer attempts per 1000 youths [95%CI, 1.8–8.0 fewer attempts per 1000 youths]; p = 0.003). There was no evidence of longer-term differences in suicide attempt rates.Suicide Counties implementing GLS training had significantly lower suicide rates among the population aged 10–24 years in the year after GLS training than similar counties that did not implement GLS training (1.33 fewer deaths per 100,000; p = 0.02). No evidence of an effect beyond one year after training implementation.Matsubayashi & Ueda (2011) [133]Multi-nationalStudy interrupted time series with a control groupLevel of III-2Target region/ 21 OECDnationsComparison: 10 OECD countries without a national suicide prevention programMultiple: National prevention programs - specific interventions not specified or analyzed.1980–2004One time period, statistical models include date of implementation of suicide prevention program - varies for each countryWere data collected at multiple time points? NoWas the intervention likely to affect data collection? No: National mortality data.Suicide: Suicide rates in under 25 year-olds, obtained via the WHO mortality databaseSuicide: 20.901(mean total rate)Suicide Suicide prevention programs have a negative impact on the suicide rate (Males: − 1.33, SE 0.5; p < 0.05; Females − 0.276 SE.08, p < 0.05)Notes: NSDUH = National Survey on Drug Use and Health; NA = not applicable; NR = not reported; OECD = Organization for Economic Co-operation and Development; WHO = World Health Organization; SA = suicide attempt; SE = standard error; SES = socio-economic status; SH = self-harm; SI = suicidal ideation; SRB = suicide-related behavior.aDefined as at least twice before or at least twice after implementation of the intervention.bNote: it is likely that this study is a subset of the date included in Wheeler et al (2009).Table 6Non-randomized experimental trials in community settings (N = 1).Table 6Study; countryStudy design; level of evidenceTarget populationParticipantsIntervention descriptionComparison conditionRisk of biasSuicide related outcome(s) assessed; Longest follow-upResultsInterpretationAllen et al. (2017)USA [138]Study Non-randomized experimental trialLevel of III-2Inclusion: Young people living in Yup'ik communitiesExclusion: NoneRecruited Yup'ik communities in southwest AlaskaWhole sampleN = 124Mean NRGender: NRTreatment groupN = 128Mean age (SD): 14.24(1.72)Gender: 43% maleControl groupN = 74Mean age (SD): 14.62(1.82)Gender: 73% maleQungasvik: A cultural intervention based in a local,Indigenous theory of personal and community change. Modules are individual, family, or community level.Length: one or more 1–3 h sessions.Developed study authorsDelivered different cultural experts.Community 2 – exposed to less-intensive intervention.Intervention Rasmus et al. (2014)aAdequately NRWas SH a pre-determined NoOutcome assessor NRLess than 15% drop-out rate for DSH at post-intervention: UnclearUse of statistical testing to measure change from pre-test to post-test: YesSI: “A Way to Live a Very Good, BeautifulLife”—Reasons for Life (RL): a cultural adaptation and strengths-based extension of the Brief Reasons for LivingInventory for Adolescents.Longest follow-up: post-interventionSI: Post-intervention: Intervention mean (SD): 22.42 (4.99)Control mean (SD): 62.98 (17.49)The treatment group showed a greater reduction in SI (indicated by increased scores on the RL) than the control group (d = 0.28, p < 0.05),Notes: NR = not reported; SD = standard deviation; SI = suicidal ideation.aRasmus SM, et al. Creating Qungasvik (a Yup'ik intervention “toolbox”): Case examples from a community-developed and culturally-driven intervention. Am J Community Psychol 2014; 140–152.

The majority of studies were conducted in the United States of America (k = 49; 49·5%), followed by the United Kingdom (k = 12; 12·1%) and Australia (k = 11; 11·1%). Some were conducted across multiple countries and only two (2·0%) were conducted in low-middle income countries. The number of studies more than doubled in the period of 2005–2017 compared to 1990–2004.

Studies Conducted in Clinical Settings

Fifty-two of the included studies were conducted in clinical settings and all tested indicated interventions delivered to young people with a history of self-harm or attempted suicide resulting in presentation to hospital-based or mental health services. Outcomes therefore refer to repeated self-harm in these studies. Thirty-three were RCTs. Forty (76.9%) had a mean participant age of 18 years or younger, eight studies (15.4%) had a mean age over 18, and in four studies (7.7%) the mean age could not be determined.

Randomized Controlled Trials

Study Description

Participants were recruited from emergency departments, inpatient units and community mental health services/outpatient clinics. One study was set in a military hospital [40]. Studies examined the impact of a range of interventions, including individual and group cognitive behavioral therapy (CBT), dialectical behavioral therapy (DBT), family therapy, and brief contact interventions. Control conditions included TAU, e.g. routine care, enhanced TAU, e.g. safety monitoring and facilitated referrals, and active placebo e.g. problem oriented support but without a specific skills-based training component. Twenty-four (72*·*7%) of the studies in this category included participants with a mean age of 18 or younger. Please see Table 1.

Study Efficacy

Thirty-two of the 33 clinical RCTs reported data amenable to meta-analysis. Twenty-five were psychological interventions [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64] and seven were brief contact interventions [65], [66], [67], [68], [69], [70], [71]. The results of the meta-analysis, classified according to outcome assessed, are reported below. The primary outcome (self-harm) is reported first, followed by suicidal ideation; suicide is reported last as it was least frequently assessed.

Self-harm Measured Dichotomously

Compared to controls, there was no evidence of any intervention effect on self-harm at post-intervention (k = 12, RR = 0·889, 95% CI 0·71 to 1·11, I^2^ = 37·1%) (Fig. 2). At follow-up there was some evidence of a reduction in the proportion of people who had received an intervention who went on to have a repeat self-harm episode (k = 16, RR = 0·83, 95% CI 0·70 to 0·99, I^2^ = 40·9%) (Fig. 3).Fig. 2Random effects risk ratio and 95% confidence interval (CI) for clinical interventions at the post-intervention assessment.Fig. 2Fig. 3Random effects risk ratio and 95% confidence interval (CI) for clinical interventions at the longest follow-up assessment.Fig. 3

Sensitivity Analysis

There was no material change to the outcome at post-intervention when studies at high risk of bias for allocation concealment were removed. At follow-up, when studies at high risk of bias were removed, the effect was no longer significant.

Subgroup Analysis

There was no evidence that the type of intervention modified the size of the treatment effect post-intervention (p = 0·67) or at follow-up (p = 0·09); nor was there any evidence that therapy modality modified the size of the treatment effect post-intervention (p = 0·13), or at follow-up (p = 0·08).

Self-harm Measured Continuousl

Compared to controls, there was little evidence, with high heterogeneity (I^2^ = 94·4%), that the intervention resulted in a reduction in the mean number of self-harm episodes at post-intervention (k = 5, SMD = − 0·66, 95% CI − 1·45 to 0·13), and there was limited evidence of this at follow-up (k = 4, SMD = − 0·23, 95% CI − 0·49 to 0·03, I^2^ = 38·9).

Suicidal Ideation Measured Dichotomously

Compared to controls, there was no evidence of any effect of intervention on the proportion of people who experienced suicidal ideation post-intervention (k = 7, RR = 0·89, 95% CI 0·68 to 1·16, I^2^ = 83·0%) or at follow-up (k = 5; RR = 0·84, 95% CI 0·64 to 1·09, I^2^ = 74·8%). Heterogeneity was high.

Suicidal Ideation Measured Continuously

Compared to controls, there was strong evidence of a small effect of the intervention on suicidal ideation post-intervention (k = 15, SMD = − 0·28, 95% CI − 0·48 to − 0·08, I^2^ = 76·3%). The effect was smaller at follow-up (k = 11, SMD = − 0·18, 95% CI − 0·34 to − 0·02, I^2^ = 41·1%).

One RCT in this category was not included in the meta-analysis. This investigated the impact of Parent-Adolescent CBT [72]; authors reported reduced suicidal ideation in both groups during active and maintenance treatment and at follow-up.

Study Quality

The majority of these studies used random sequence generation [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [53], [54], [55], [56], [58], [59], [61], [62], [64], [65], [66], [67], [68], [69], [70], [71] (k = 28; 84·8%) and 21 (60·6%) used adequate allocation concealment strategies [42], [43], [44], [45], [46], [49], [50], [51], [53], [54], [55], [58], [59], [61], [62], [64], [65], [66], [67], [69], [70]. Of the 25 studies that assessed outcomes via interview, 13 (52·0%) reported assessor blinding [43], [44], [45], [49], [51], [53], [55], [56], [59], [61], [64], [65], [70]. Thirteen studies reported conducting intention-to-treat (ITT) analysis [42], [46], [48], [53], [54], [56], [58], [59], [61], [64], [65], [69], [72]. One study did not use ITT, but conducted a sensitivity analysis to assess the robustness of the findings [70]. Nineteen (57·6%) reported less than 15% drop out and were classed as low risk for the purpose of meta-analysis [41], [43], [44], [45], [46], [49], [50], [51], [53], [54], [56], [58], [61], [63], [64], [65], [66], [67], [68], [69].

Other Study Designs

Study Description

All nineteen studies in this category tested indicated therapeutic interventions. The majority employed a pre-test/post-case series study design (k = 11; 57·9%) [73], [74], [75], [76], [77], [78], [79], [80], [81], [82], [83]. Sixteen (84·2%) recruited participants from community mental health services or hospitals, including inpatient and emergency department settings [73], [74], [75], [76], [77], [78], [79], [80], [83], [84], [85], [86], [87], [88], [89], [90], [91]. Interventions included DBT, CBT, and brief contact interventions. Sixteen (84.2%) of the studies in this category had a mean age of 18 or younger. Please see Table 2.

Study Efficacy

Two of the five studies testing a CBT-based intervention reported reductions in suicide-related behaviour [73], [86], and three reported reductions in suicidal ideation [73], [75], [76]. Five of the six studies testing DBT reported reductions in suicide-related behaviour [74], [77], [79], [80], [88], and four reported reductions in suicidal ideation [74], [77], [84], [88]. Two of the three studies testing family-based interventions reported reductions in suicidal ideation [83], [89], and one reported a reduction in suicide attempts [89]. One study reported a reduction in the proportion of young people reporting a suicide attempt following exposure to a crisis intervention program [78], and one reported reduced suicidal ideation following telephone counseling [81]. One study tested a brief contact intervention and reported no between-group differences [85]. A study of a problem solving intervention reported a reduction in the proportion of participants reporting suicide attempts in the treatment group compared to controls [87]. Finally, a study testing an intervention for American Indians reported reductions in suicidal ideation over time [82]. Significance testing was not always conducted or reported for studies in this category.

Study Quality

Only seven studies had dropout rates of less than 15% [73], [78], [81], [83], [84], [86], [89]. All but one [89] were either under-powered or the adequacy of the sample size could not be determined. Eight studies used a comparison group [84], [85], [86], [87], [88], [89], [90], [91]. Three assessed outcomes using interview-rated measures [87], [90], [91], and only one reported that outcome assessors were blinded to treatment allocation [91]. Fifteen studies (78·9%) conducted statistical testing to measure change from baseline [73], [74], [75], [77], [79], [80], [81], [82], [83], [84], [85], [86], [88], [89], [91].

Studies Conducted in Educational and Workplace Settings

Thirty-one studies recruited participants from educational or workplace settings; of these 21 (67·7%) were conducted in schools [92], [93], [94], [95], [96], [97], [98], [99], [100], [101], [102], [103], [104], [105], [106], [107], [108], [109], [110], [111], [112], seven (22·6%) in universities [113], [114], [115], [116], [117], [118], [119], two (6·5%) in military-based workplace settings [120], [121], and one (3·2%) from both schools and public places in the community [122]. Twenty-one (67*·7%) had a mean participant age of 18 years or younger, eight studies (25.8%) had a mean age over 18, and in two studies (6·*5%) the mean age could not be determined. Fifteen (48.4%) were RCTs.

Randomized Controlled Trials

Study Description

Three of the RCTs tested universal interventions [92], [113], [119], nine tested indicated interventions [95], [96], [97], [98], [114], [115], [116], [122], [123], and three tested multi-modal or multiple interventions [99], [100], [101]. Studies were either educational or therapeutic in nature, and four tested an internet-based intervention [113], [119], [122], [123]. One large cluster-RCT tested three distinct interventions (workshops for students; gatekeeper training; and screening) [101]. Two multimodal studies combined a universal educational component with screening. Examples of control conditions in these studies included TAU e.g. an interview with a school counselor, enhanced TAU, e.g. weekly therapy, and placebo e.g. a video about unrelated health issues. Ten studies (66*·*7%) in this category included participants with a mean age of 18 or under. See Table 3.

Study Efficacy

Eleven RCTs reported data amenable to meta-analysis [92], [98], [99], [101], [113], [114], [115], [116], [119], [122], [123]. Together there were 13 individual intervention arms because one study tested three interventions (one brief contact intervention and two universal educational interventions) [101]. Two intervention arms were brief contact interventions, five were universal educational interventions, and six were psychological interventions. As above findings are presented according to the outcome assessed, with the primary outcome (self-harm) reported first, followed by suicidal ideation. No studies reported suicide as an outcome.

Self-harm Measured Dichotomously

Compared to control, there was evidence of an intervention effect on self-harm at post-intervention (k = 3, RR = 0·31, 95% CI 0·15 to 0·61, I^2^ = 0%) (Fig. 4) and at follow-up (k = 3, RR = 0·63, 95% CI 0·42 to 0·96, I^2^ = 0%) (Fig. 5).Fig. 4Random effects risk ratio and 95% confidence interval (CI) for educational interventions at the post-intervention assessment.Fig. 4Fig. 5Random effects risk ratio and 95% confidence interval (CI) for educational interventions at the longest follow-up assessment.Fig. 5

Sensitivity and Subgroup Analysis

As there were only three studies in this category these analyses were not possible.

Self-harm Measured Continuously

Compared to control, there was one study that reported continuous data post-intervention [115] with little evidence of an effect (k = 1, SMD = − 0·16, 95% CI − 0·61 to 0·30). No studies reported follow-up data for this outcome.

Suicidal Ideation Measured Dichotomously

Compared to control, there was little evidence of an effect at post-intervention (k = 1, RR = 0·76, 95% CI 0·50 to 1·16) or follow-up (k = 2 (4 intervention arms), RR = 0·72, 95% CI 0·51 to 1·03, I^2^ = 0%).

Suicidal Ideation Measured Continuously

Compared to control, there was strong evidence of an effect of the intervention on suicidal ideation at post-intervention (k = 7, SMD = − 0·41, 95% CI − 0·57 to − 0·24, I^2^ = 15·2%). By follow-up, the effect was no longer significant (k = 5, SMD = − 0·21, 95% CI − 0·52 to 0·1, I^2^ = 46·9%).

Four RCTs were not included in the meta-analysis. One tested a supportive intervention and found decreases in ‘suicide risk behaviors’ in treatment and control groups, but no between-group differences [95]. One examined a parent-specific intervention and found reductions over time in both groups, with greater reductions in the treatment group [96]. A group ‘coping with stress course’ tested with African-American adolescents was associated with a relative risk reduction in suicide in the intervention group compared to controls [97]. Finally, a multimodal intervention combining psycho-education and screening was associated with reduced suicidal ideation and behavior in intervention participants compared to controls [100].

Study Quality

Seven studies (46·7%) reported using random sequence generation techniques [95], [99], [100], [101], [116], [122], [123] and only three (20·0%) reported adequate concealment of treatment allocation [113], [122], [123]. None of the studies in this category assessed primary outcomes using interviews, so outcome assessor blinding is not applicable. Six (40·0%) studies used ITT analysis [98], [113], [116], [119], [122], [123]. One third (k = 5) had dropout rates of less than 15% [92], [97], [98], [113], [122].

Other Study Designs

Study Description

Of these 16 studies, four were non-randomized experimental trials [93], [94], [103], [107], [117], four were pre-test/post-test case series studies [102], [108], [110], [112], three were post-test case series studies [104], [105], [106], and four employed an interrupted time series design [109], [118], [120], [121]. The majority were conducted in school settings (k = 12; 75·0%), with two each (12·5%) conducted in university [117], [118] and military settings [120], [121]. Five studies tested universal educational programs [93], [94], [102], [103], [110], two evaluated selective interventions [104], [121], five evaluated indicated interventions [105], [106], [112], [117], [118] and four evaluated multimodal interventions [93], [94], [102], [103], [107], [108], [109], [110], [120]. Two studies evaluated online interventions [108], [112]. Eleven studies (68.8%) in this category had a mean participant age of 18 or under. See Table 4.

Study Efficacy

Of the five studies testing universal interventions, one reported a reduction in suicide-related behavior post-intervention [94], one reported a reduction in suicidal ideation post-intervention and at follow-up [110], and one reported a reduction at follow-up only [102]. Two studies tested selective one showed no effect of a counseling session delivered to school students bereaved by suicide [104] and the second reported a reduction in suicide attempts associated with a training intervention delivered to U.S. naval instructors [121].

Two of the five studies testing indicated interventions assessed suicide rates as the outcome of interest. The first found no impact of a therapeutic program among secondary school students [105]. The second examined the impact of a university suicide prevention policy and reported a reduction among the intervention group compared to increases among controls [118]. Of the remaining three studies of indicated interventions, only one therapeutic-based intervention was associated with a reduction in suicidal ideation from pre- to post-test [112].

Four studies tested a multimodal intervention. One was conducted in a workplace setting and reported lower suicide rates at post-intervention [120]. Two studies reported decreases in suicide attempts [107], [109]. The final study examined the impact of a combined therapeutic and screening intervention and reported reductions in suicidal ideation at post-intervention and follow-up [108].

Study Quality

Only one study [117] reported an attrition rate of less than 15%. Three studies were adequately powered [105], [108], [120], and in another three, although no power calculations were provided, the sample size was sufficient to examine changes in suicidal ideation but not self-harm [102], [107], [109]. The majority of studies (k = 12; 75·0%) used statistical testing to measure change from pre- to post-test [93], [94], [102], [104], [106], [108], [110], [112], [117], [118], [120], [121].

Studies Conducted in Community Settings

Study Description

Fourteen studies in this category (87·5%) were interrupted time series studies [124], [125], [126], [127], [128], [129], [130], [131], [132], [133], [134], [135], [136], [137]; two (14·3%) utilized a control group [124], [133]. One study was a non-randomized experimental trial [138] and one was an ecological study [139]. None of the community-based studies were RCTs. Eight (50·0%) evaluated means restriction approaches, five (31·3%) tested multimodal interventions [124], [127], [129], [130], [134] and two (12·5%) evaluated multiple interventions [133], [139]. One non-randomized experimental trial [138] examined the impact of a cultural intervention among indigenous young people in Alaska.

Study Efficacy

Five of the six studies examining the impact of policies designed to restrict access to firearms reported decreases in the firearm suicide rate among young people [125], [126], [128], [132], [135], and one reported an increase [131]. Only one reported a decrease in the overall youth suicide rate [132].

Two studies examined the impact of regulatory action to restrict use of antidepressants and found no evidence of an effect on suicide rates [136], [137]. One of these studies also examined the impact of such regulatory action on rates of hospital admissions for self-harm and reported decreases in females only [136].

Three of the five studies evaluating multimodal interventions reported generally positive impacts on rates of suicide and/or suicide-related behaviour [127], [130], [134]. One study found the suicide rate decreased by 5·5% in 15–19 year-olds but increased by 38% in 10–14 year-olds [129]. Finally, one study evaluated the impact of an intervention targeting self-immolation in women; the authors reported a reduction in the number and percentage of self-immolation cases but did not report statistical significance [124].

One study evaluated multiple interventions delivered across different counties in the U.S. The interventions were associated with lower rates of suicide attempt [139] and suicide [38] but there was no evidence of a longer-term effect. Finally, a study evaluating the impact of government-initiated national suicide prevention programs across multiple nations reported decreases in suicide rates [133].

Study Quality

In 11 studies (73·3%), data were collected at multiple time points [125], [126], [127], [128], [129], [130], [131], [134], [135], [136], [137] and in 11 studies the intervention was deemed unlikely to impact data collection for the primary outcome of interest [125], [126], [128], [130], [131], [132], [133], [135], [136], [137], [139].

Discussion

This review examined 99 individual studies of interventions designed to reduce suicide-related behaviors among young people. Samples were diverse, although few studies were conducted in low-to-middle income countries. Studies were conducted across a range of settings and tested a variety of intervention approaches, reflecting the spread of suicide prevention activity as recommended by current policy [7], [1]. Less than half the studies were RCTs, which is unsurprising as the lack of RCTs in suicide prevention has been highlighted previously [24], [140]. Although not all intervention approaches, or intervention types, lend themselves to being tested this way, there remains a clear need for high-quality intervention studies in this field. In the majority of studies the mean age of participants was 18 or under (68.7%). In the clinical studies this was more prominent than in those conducted in educational settings (76.9% compared to 67.7%), suggesting that the findings from the clinical trials may be most applicable to young people aged 18 and under.

The number of intervention studies in youth suicide prevention has doubled in recent years, which is encouraging. However, many studies tested interventions originally designed for adults with little, or no, adaption for young people [24]. This may partially account for the high rates of attrition in many of the studies reviewed. Adolescence and young adulthood are developmental periods requiring specific attention [141], [142]. As such interventions that account for developmental stage and are both acceptable to, and ideally co-designed with, young people are necessary.

The meta-analysis showed little evidence that interventions reduced repetition of self-harm at post-intervention in clinical settings. Whilst there was some evidence for reduced repetition of self-harm at follow-up, this effect disappeared after removing low-quality studies; as such these findings should be interpreted with caution. There may be a small effect on frequency of self-harm measured continuously. It is possible that these effects are being driven by the large trial by Hassanian-Moghaddam and colleagues that tested a brief contact intervention in Iran [68]. This finding is in contrast to a review by Ougrin and colleagues, which found evidence of benefit for clinical interventions in reducing the proportion of adolescents re-engaging in repeat self-harm [143]. This variation in findings may be explained by the settings in which the studies were conducted, or may be attributable to methodological differences such as the more specific inclusion criteria employed by the current review and/or differences in reporting of results (i.e., use of relative vs absolute effect size). There was also strong evidence of a small effect on suicidal ideation at post-intervention, and to a lesser extent at follow-up, again possibly being driven by the large Hassanian-Moghaddam trial [ 68].

There is less evidence for interventions delivered in educational or workplace settings given that fewer methodologically-rigorous studies have been conducted. Of note are the large studies conducted by Wasserman and colleagues [101] and Schilling and colleagues [99]. The educational components of the interventions tested in these studies appeared to reduce self-harm at post-intervention and at follow-up [99], [100], [101], although there were too few studies to conduct meaningful sub-group analyses. There was also an effect on suicidal ideation at post-intervention, but not follow-up. Overall these results indicate that school-based psycho-educational interventions that are coupled with screening have the potential to be effective, however the robustness of findings is hampered by study quality.

To some extent the overall limited effects detected may reflect a lack of statistical power, either due to small sample sizes at baseline or high attrition rates. Many studies (in particular those of indicated interventions) were underpowered and did not find statistically significant improvements despite the direction of effect being positive. This was particularly true for studies examining self-harm given the large sample sizes required to detect an effect [144]. It may also be that suicidal ideation and self-harm are different constructs, and whilst it is largely accepted that they exist along a continuum [145], specific processes may facilitate the transition from suicidal ideation to suicide attempt [146]. It may therefore be the case that existing interventions more effectively target suicidal ideation than self-harm, and that interventions with stronger theoretical underpinnings are required to reduce self-harm and suicide. Further work delineating the modifiable risk and protective factors associated with repeated self-harm is therefore required [147].

Evidence regarding the efficacy of interventions in community settings was mixed. The studies that examined the impact of multimodal interventions generally reported reductions in rates of suicide and/or self-harm, although study quality was variable. These findings are encouraging given the emphasis in many countries on place-based responses to suicide prevention [148], [149]. The interventions tested typically comprised universal educational programs, gatekeeper training, screening, and treatment responses where appropriate, and appeared to positively impact young people. These intervention types should be included in future place-based approaches and subject to rigorous testing.

Means restriction, such as reducing access to known jumping sites, has long been considered an effective suicide prevention intervention [17], [18]. Our review identified few studies examining the effects of means restriction on young people, and those that did focused on firearm restriction. These were generally associated with decreases in rates of firearm suicide, but no reduction in overall youth suicides. An explanation may be that firearm suicides are relatively uncommon among youth in the countries studied. For example, three studies were conducted in Canada where the most common method of youth suicide is hanging [150]. It stands to reason that restricting access to a particular method will only reduce overall suicide rates if it is a method commonly used by the population.

Despite the spread of studies across intervention types and settings, gaps existed. For example, General Practitioners (GPs) are often a first port of call for young people yet there were no studies in primary care settings. GPs and have identified the need for training in youth suicide prevention [151]; as such primary care settings may provide an opportunity for intervention early in the suicidal trajectory that is currently being missed. Additionally, few studies were conducted in universities or workplaces compared to schools. Given that suicide rates are highest post-school age [152], tertiary education facilities and workplaces are key settings for future suicide prevention efforts and greater evidence is required [142], [153]. Moreover, only six studies tested online interventions; all were in educational settings. There is increasing evidence supporting the efficacy of online interventions in the treatment of depression and anxiety [154], as well as evidence supporting their acceptability with young people at risk of suicide and potential to reduce risk [155]. All the studies of online interventions were CBT-based and most appeared to show promise, raising the question of why online interventions are not being trialed in clinical settings. This is an important avenue for youth suicide prevention yet to be capitalized on.

Finally, there are some groups who are underrepresented in this research. Only three studies [93], [94], [138] tested interventions among indigenous young people, despite this group being at elevated risk in many countries [156]. Similarly, same-sex-attracted and gender diverse young people are at elevated risk of suicide [157], yet only one study specifically targeted same-sex attracted youth [83]. Whilst this may be partially due to methodological challenges [156], [158], generating evidence regarding effective suicide prevention approaches for these populations must be a priority. Related to this, females were over-represented in the studies reviewed. This is unsurprising given the higher rates of both self-harm and help-seeking among females compared to males [159], [160], however there is a lack of knowledge regarding effective interventions for young men, whose rates of suicide are three times those of females [1].

A strength of this review is the inclusion criteria used. These were both broad (e.g., no restrictions on intervention approach or study design) and specific (i.e., studies tested interventions that were specifically designed for suicide prevention and reported suicide-related outcome data). Whilst some potentially effective interventions may have been excluded (e.g., those designed to treat or prevent depression), this review is well-placed to provide guidance regarding what does and does not impact suicide-related outcomes in young people. Despite this, some limitations must be addressed.

Firstly, the broad scope of the review, together with time and resource constraints, required us to make a number of pragmatic methodological decisions. For example, we adopted a pragmatic approach to assessing study quality, as applying standard Risk of Bias criteria to the non-RCTs would result in a low quality rating for all studies. Although we acknowledge the high risk of bias associated with non-randomized study designs, ethical and methodological barriers often prevent suicide prevention researchers from conducting RCTs. To accommodate this, the quality of non-RCTs was assessed using a tool appropriate to that design. Overall, however, study quality was limited. Indeed, many RCTs were not reported according to the Consort statement [161] and many were underpowered. Whilst this is not uncommon in suicide prevention research [144], priority needs to be given to well-designed, sufficiently powered studies. Additionally, for pragmatic reasons we did not include analysis of publication bias in our analysis of study quality. Other minor methodological limitations relate to our decisions not to prospectively register the review and not to contact key authors in the field. Although these steps are encouraged, they are not a requirement of compliance with the PRISMA statement and were not anticipated to impact the results; therefore due to time and resource constraints they were not a part of the present review.

A third limitation relates to the quality of the studies included in the meta-analysis, the results of which should be treated with caution. Additionally, on several occasions different studies contributed data to the post-intervention and follow-up outcomes. We therefore cannot be certain that changes at follow-up are in fact the result of a true reduction in the treatment effect over time. There was also heterogeneity in the control conditions and in the outcome measures used between studies, limiting our ability to be confident that studies measured the same constructs. For example, methods to assess self-harm included self-report instruments, hospital data and clinician-rated interviews. It was also often unclear if measures had been validated among young people. Researchers have previously called for the use of well-validated and standardized measures in adult suicide research, and we argue the same is required in studies with youth [162].

Finally, we acknowledge that a number of relevant studies have been published since the search was conducted. For example, a 2018 RCT trial found no benefit of systemic family therapy compared to treatment as usual in reducing subsequent hospital presentations for young people who self-harm [163]. Another RCT found DBT was more effective in reducing repeat suicide attempts in adolescents, compared to individual and group supportive therapy [164]. Although these studies both meet criteria for inclusion in the current review they were published after our search was conducted.

Conclusion

This review identified a large number of studies testing a broad range of interventions across multiple settings. We found that some interventions for example, brief contact interventions in clinical settings, and psychoeducation combined with screening in school settings can reduce the frequency of self-harm and suicidal ideation, although it is likely the size of these studies that is driving the effects. Large-scale multimodal interventions also show promise. Despite these promising findings there remains a paucity of high-quality youth suicide prevention intervention studies. Whilst not all interventions lend themselves to testing via RCTs, other robust study designs can and should be employed. Additionally, many studies, particularly those in clinical and community settings, tend to test interventions originally designed for adults. By focusing suicide prevention efforts on generic, as opposed to youth-specific, interventions, we are likely missing crucial opportunities for intervention, such as delivery via online platforms. Future research should adapt known effective interventions for young people, and for delivery online. A focus on university and workplace settings is also warranted.

Although young people have repeatedly been identified by suicide prevention policy as a group requiring specific attention, their suicide rates are rising. To reverse this trend, we need more large-scale methodologically-rigorous studies that develop and test new approaches. These approaches should be acceptable to all young people and capitalize on the ways in which young people interact with the health system, supports, and services.

The following is the supplementary data related to this article.AppendixSearch terms.Appendix

Supplementary data to this article can be found online at https://doi.org/10.1016/j.eclinm.2018.10.004.