Authors: E. Doña-López, M. Godoy-González, G. Navarra-Ventura, A. Fernández-Olivares, G. Gomà, J. Estela Esteve, C. De Haro, E. Diaz Santos, L. Salarbous, M. Jodar, L. Blanch, J. López-Aguilar, S. Fernández-Gonzalo
Categories: Article, Emotional distress, Physical distress, Dyspnea, Pain, Anxiety, Sadness, ICU, Critically ill patients
Source: Scientific Reports
Authors: E. Doña-López, M. Godoy-González, G. Navarra-Ventura, A. Fernández-Olivares, G. Gomà, J. Estela Esteve, C. De Haro, E. Diaz Santos, L. Salarbous, M. Jodar, L. Blanch, J. López-Aguilar, S. Fernández-Gonzalo
Emotional distress, including anxiety and sadness, is common among patients in the intensive care unit (ICU). It may be influenced by clinical factors but also by physical distress symptoms such as dyspnea and pain; however, trajectories of emotional and physical distress and interactions throughout the ICU stay, and their potential impact after discharge, remain relatively unexplored. The main objective of the study was to investigate the trajectory and interplay of anxiety, sadness, dyspnea, and pain during the ICU stay, and also their associations with clinical and demographic factors and with cognitive status at discharge. Observational, longitudinal study in non-delirious adult ICU patients in whom emotional state (anxiety and sadness) and physical discomfort (dyspnea and pain) were assessed daily using a visual analog scale, once an adequate level of consciousness (RASS between − 1 and + 1) had been achieved. A new variable was created to compare the evolution of distress in the different phases of admission. Mixed-effects models were used to explore associations with the phase of ICU stay, invasive mechanical ventilation (IMV), and other clinical variables. Cognitive status was assessed at ICU discharge with the MoCA test. In 62 ICU patients, levels of sadness consistently exceeded anxiety during ICU stay, although both remained stable and declined only in the final phase. IMV was associated with higher levels of sadness (β = 2.45, p < 0.001) and dyspnea (β = 1.24, p = 0.003). Male patients reported lower anxiety levels (β = − 1.34, p = 0.039). Pain correlated with sadness early in the ICU period (r = 0.44, p = 0.016), and with dyspnea during the second (r = 0.54, p = 0.001) and late phases (r = 0.34, p = 0.004). At ICU discharge, 70.9% of patients showed cognitive impairment unrelated to distress, clinical or demographic variables. Sadness was identified as a more prominent component of emotional distress than anxiety during the ICU stay. The findings underscore the impact of IMV on both sadness and dyspnea, highlighting the value of a multidimensional psychological assessment in critically ill patients. The lack of association between cognitive impairment at discharge and in-ICU emotional/physical distress trajectories suggests that cognitive and emotional sequelae may arise from distinct underlying mechanisms.
Trial registration: ClinicalTrials.gov (NCT07153380).
The online version contains supplementary material available at 10.1038/s41598-026-36684-y.
Admission to the ICU can be a frightening and stressful event that generates high emotional distress in critically ill patients. The prevalence of anxiety and depression symptoms in critically ill patients during the ICU stay is estimated to range between 24 and 29% and 13.7 and 35% respectively^1,2^, although in some studies these percentages are as high as 84.3% for anxiety and 79.6% for depression^3^. During critical illness and its management, patients may also endure physical distress in the form of dyspnea and pain which may further exacerbate their emotional distress during the ICU stay^4–6^.
Multiple factors have been associated with the levels of emotional and physical distress related to ICU stays. These factors can be broadly categorized into individual patient characteristics such as age, gender, and educational level, and clinical factors, including ICU length of stay and the need for invasive mechanical ventilation (IMV)^7,8^. The gender differences observed in intensive care patients are still poorly understood and require further research^1,9,10^. However, female sex appears to entail a greater risk for developing emotional sequelae both during and after the ICU stay^11–13^, as women manifest higher levels of anxiety and depression symptoms^14^.
IMV has been identified as a clinical factor that plays a central role in the development of emotional and physical symptoms of distress during and after the ICU stay, exerting a significant impact on the well-being of patients^12,15,16^. Patients on mechanical ventilation are nine times more likely to experience anxiety if they also suffer dyspnea^17^. Dyspnea, defined as a subjective experience of respiratory difficulty, is a complex process which interacts with anxiety^18–20^. Moreover, some evidence suggests that dyspnea is multidimensional, leading to increased anxiety and depression when it persists despite behavioral adjustments^21^, or when it appears in unpredictable conditions^22^. Dyspnea is highly prevalent among critically ill patients, especially those requiring IMV, and has been associated with increased emotional distress, exacerbating symptoms during and after the ICU stay^17,23–25^. Although previous results suggest sex-based differences in the risk factors for prolonged IMV^26^, further research is needed on the interaction between gender, IMV, dyspnea and emotional state during ICU admission.
Two other main triggers of emotional distress in the critically ill patient are pain and the presence of delirium^27–29^. Pain has been associated with anxiety symptoms^30^, greater psychological distress upon discharge, long-term psychological stress and the development of PTSD symptoms^31–33^, and depressive symptoms^34–37^. Interestingly, the presence of anxiety and depression symptoms in critically ill patients at admission has also been associated with increased ICU delirium^38^, and in fact delirium is the factor most robustly associated with post-ICU cognitive difficulties^39^. Thus, the increases in anxiety and depression symptoms observed in critically ill patients could be attributed to a multitude of clinical factors and physical stressors present in the ICU environment and the critical illness management^4,40,41^.
Despite the high prevalence of emotional distress during critical illness, few studies have specifically assessed the trajectories of anxiety and depression symptoms over the course of the ICU stay. Several barriers hinder the assessment of emotional and physical distress in critically ill patients such as their inability to describe their condition and the presence of delirium, sedation, or endotracheal intubation^42,43^. This gap in the literature highlights the need for further research to understand the complex and multidimensional trajectories of emotional distress during ICU admission, which are influenced by physical stressors, individuals’ characteristics and clinical factors, and to assess their potential impact on post-discharge sequelae including cognitive difficulties.
This study aimed to explore the trajectory and interplay of emotional and physical distress over the course of the ICU stay in critically ill patients with and without the need for IMV.
The secondary objectives To characterize the trajectories of emotional and physical distress during the ICU stay.To explore demographic and clinical factors related to the development and progression of emotional and physical distress during ICU admission.To examine in depth the interplay between physical stressors, such as dyspnea and pain, and emotional state during ICU stay.To explore the impact of the emotional and physical distress trajectories during critical illness on cognitive status at ICU discharge.
Observational study integrating longitudinal data from three independent prospective cohorts of critically ill patients admitted at the Parc Tauli University Hospital. The first cohort was recruited between November 2018 and February 2020 (n = 26), the second between November 2021 and January 2023 (n = 65) and the third between September 2022 and September 2024 (n = 77).
Data collection for each cohort was independently approved by the Institutional Review Board of the Parc Tauli University Hospital (2018/542, 2021/5088, 2022/6011). The reanalysis for the current project was approved. (2025/5057) and registered on ClinicalTrials.gov (NCT07153380) on September 3, 2025. All methods were performed in accordance with the relevant guidelines and regulations. All participants (or their authorized representatives) provided written informed consent prior to inclusion in the study.
To ensure the methodological rigor of the study, only ICU patients who had completed the emotional state assessment on at least 80% of the days with adequate levels of consciousness (Richmond Agitation-Sedation Scale, RASS, between − 1 and + 1) and who were free of delirium at the time of assessment were included in the analysis. This threshold was established as a balance between data reliability and sample retention, given that daily emotional assessments were not recorded in all patients.
The three cohorts included critically ill patients ≥ 18 years old, admitted to the ICU for at least 24 h. Patients with a history of cognitive impairment or dementia, prior neurological disease (including brain damage at admission) or severe psychiatric disorder (including substance use disorder), intellectual disability, inability to speak Spanish, life expectancy < 12 months or refusal to participate in the study were excluded. In patients ≥ 65 years old, pre-existing cognitive impairment upon ICU admission was assessed using the Spanish version of the Short Form of the Informant Questionnaire on Cognitive Decline in the Elderly (Short-IQCODE)^44^. This questionnaire was administered to family members to determine the presence of previous cognitive decline, with a cutoff score greater than 57 indicating impairment. Patients admitted to the ICU were screened daily by an intensive care nurse. Written informed consent was obtained from each patient or their authorized representatives at the time of inclusion in the study. If consent was initially provided by an authorized representative (e.g., in the case of a comatose, deeply sedated or delirious patient), it was subsequently ratified by the patient once they regained mental competence.
At study inclusion, disease severity and comorbidity levels were assessed using the Acute Physiology and Chronic Health Evaluation II (APACHE II)^45^ and the Charlson Comorbidity Index^46^ respectively. The level of consciousness was recorded daily with the Richmond Agitation-Sedation Scale (RASS; Sessler et al., 2002) and the presence of delirium using the Confusional Assessment Method for the Intensive Care Unit (CAM-ICU)^47^ and/or review of medical records. Once patients reached an optimal level of consciousness (RASS − 1 to + 1) and the presence of delirium had been ruled out (Positive CAM-ICU ≥ 1 days), emotional (anxiety and sadness levels) and physical distress (dyspnea and pain levels) were assessed daily using the Visual Analog Scale (VAS) from 0 to 10^48^ with 0 indicating the absence of the symptom and 10 maximum intensity. Considering the critical condition of the patients and the communication difficulties characteristic of this population (caused, for example, by the need for endotracheal intubation), the VAS was chosen as the optimal method for assessing emotional and physical distress. In assessing distress each participant was asked each day to score their feelings of worry, fear and/or nervousness (from now on, anxiety), feelings of sadness, depression and/or desire to cry (from now on, sadness), shortness of breath or difficulty breathing and pain. For the interpretation of levels of emotional and physical distress, a VAS score of 1 to 4 was considered mild, 5 to 7 moderate, and 8 to 10 severe^49,50^. All patient data were collected until ICU discharge or up to maximum of 28 days after admission.
At ICU discharge, participants’ cognitive status was measured using the Montreal Cognitive Assessment (MoCA)^51^ in a single session of approximately 10 min. The MoCA is a brief screening test designed to assess cognitive function across various visuospatial ability and executive function (5 points), naming (3 points), memory (no points allocated during testing), attention (6 points), language (3 points), abstraction (2 points), delayed recall (5 points), and orientation (6 points). MoCA scores range from 0 to 30, with a score of 26 or higher indicating no cognitive impairment.
A new variable was created to compare the evolution of patients across different phases of their ICU stay, regardless of the total length of stay or the level of consciousness during admission. This variable allows the ICU stay of each patient to be divided into quartiles based on the proportion of days spent in the ICU at any evaluation point. The first quartile of ICU stay corresponds to the first 25% of days admitted to the ICU, the second (25–50%) and third (50–75%) quartiles represent the intermediate phases of admission, and the fourth quartile (75–100%) reflects the final period of ICU admission.
For each ICU stay quartile, an individual intra-patient median score was first calculated for all their available scores within that period. The distribution of these individual patient medians was then described by their median and interquartile range (IQR) for each quartile. Furthermore, the percentage of patients with an individual median score ≥ 5 was calculated.
To explore longitudinal changes in anxiety, sadness, dyspnea, and pain during ICU stay, mixed-effects models with random intercepts were constructed to account for intra-patient variability. Time-dependent covariates such as ICU stay quartiles, mechanical ventilation status (with and without IMV), and cognitive impairment (impaired/ non-impaired MoCA score) were incorporated into the model after being selected using univariate analysis. Covariates found to be significant with a p value greater than 0.1 were considered for inclusion in the multivariate analysis to simplify the models and focus on key contributors to daily outcome variability. Variable selection was guided by both statistical significance and data availability, ensuring adequate model power and representativeness. Multivariate mixed-effects models were developed, incorporating patient ID as a random effect to account for intra-patient variability and to capture longitudinal trends. This approach provided insights for analyzing symptom evolution over time while controlling for individual differences.
Patterns of missing data were analyzed using descriptive analysis. To study whether the evolution of anxiety and sadness interacted with the evolution of dyspnea and pain, a Spearman correlation analysis was performed.
Comparisons between patients with and without cognitive impairment (MoCA score ≤ 25) were performed using non-parametric tests, applying the Wilcoxon Mann–Whitney U test for pairwise comparisons in numerical variables. For categorical variables, Chi-square tests or Fisher’s exact tests were applied, as appropriate.
All statistical analyses were conducted using R version 4.2.2. A p value < 0.05 was taken to be statistically significant.
A total of 62 patients were included in the study at the time of ICU admission. Twelve (22.6%) participants belonged to the cohort with data collected prior to 10 March, 2020, and the remaining 48 (77.4%) to the cohorts with data collected from 18 November, 2021 onwards. Other demographic and clinical data are shown in Table 1.Table 1Demographic and clinical characteristics of the study sample.Variablen = 62Age (yr), median [IQR]63.45 [50.49, 71.21]Male, n (%)39 (62.9)Level of education, n (%) Mandatory (≤ 12 years)26 (41.9) Higher education (> 12 years)35 (56.5) Unknown1 (1.6)Cause of ICU admission, n (%) Cardiac9 (14.5) Infection/Respiratory17 (27.4) Sepsis17 (27.4) Trauma4 (6.5) Other clinical conditions (surgical complications, diabetic ketoacidosis, – gunshot wound, intestinal perforation, hemorrhagic shock)15 (24.2)Charlson Comorbidity Index, median [IQR])2.00 [0, 4]APACHE II at ICU admission, median [IQR]10.00[7,14]Length of ICU stay (days), median [IQR]5.00[3,12]Deep sedation (days), median [IQR]0.00 [0, 4]Need for deep sedation, n (%)29 (46.8)Presence of delirium, n (%)12 (19.4)Need of IMV, n (%)27 (43.5)Tracheostomy*, n (%)5 (18.5)Duration of IMV (days)*, median [IQR]6.00 [3, 11.]Cognitive status at ICU discharge (MoCA score), median [IQR])21.00[3,25]Numbers are n/total N (%) values of non-missing cases unless otherwise specified.*Data from patients who underwent IMV.APACHE II Acute Physiology and Chronic Health Evaluation II, Short-IQCODE Short Form of the Informant Questionnaire on Cognitive Decline in the Elderly, ICU intensive care unit, IMV invasive mechanical ventilation, IQR interquartile range, MoCA Montreal Cognitive Assessment.
The overall inter-patient median for anxiety was 2.5 [IQR = 0–5], with this value peaking during the second quartile of the ICU stay. For sadness, the overall median was 3 [IQR = 0–6], with values also being highest during the first half of the ICU stay. During the four quartiles of the ICU stay 32,7 to 42.8% of patients for anxiety and 34.6 to 45.7% for sadness met criteria for moderate-severe symptoms (median score ≥ 5) This prevalence was also highest in the first half of the ICU stay, peaking in the second quartile before declining.
The overall inter-patient median for dyspnea and pain remained low, at 1 [IQR = 0–3] and 0 [IQR = 0–2], respectively. The percentage of patients with moderate-severe dyspnea (median score ≥ 5) showed a consistent decline throughout the ICU stay. The percentage of patients with moderate-severe pain peaking in the second quartile before declining.
Information about the emotional and physical distress trajectories is shown in Fig. 1 and Table S1.Fig. 1Trajectories of the emotional and physical distress symptoms during ICU stay. Boxplots represent the distribution of individual patient median scores for anxiety, sadness, dyspnea, and pain across ICU stay quartiles. The red line indicates the trajectory of each variable. Individual gray dots represent the median score for a single patient within that quartile. The number of patients included in each quartile’s distribution is indicated below each boxplot.
Univariate mixed-effects models were fitted to assess the relationship between each covariate and each outcome variable (See Table S2). Four final multivariate models were developed, one for each anxiety, sadness, dyspnea and pain (Table 2 and Fig. 2). The variables included in these four models showed minimal collinearity, indicating that each one contributed distinct information to the model (See Table S3).Table 2Multivariate mixed-effects models for anxiety, sadness, dyspnea, and pain during ICU stay.Outcome variableVariableCoefficient (estimate)95% confidence intervalp valueAnxiety(Intercept)5.07[3.63, 6.51]< 0.001Gender (Male) *− 1.34[− 2.62, − 0.07]0.039Cause of admission Cardiac− 1.53[− 3.57, 0.50]0.14 Infection/respiratory − 1.94[− 3.58, − 0.29]0.021 Sepsis− 1.83[− 3.53, − 0.15]0.033 Trauma− 1.01[− 3.71, 1.70]0.466Quartile ICU stay 0–25%0.63[-0.26, 1.52]0.166 25–50%*0.88[0.10, 1.65]0.026 50–75%0.03[− 0.66, 0.73]0.925Sadness(Intercept)1.56[0.53, 2.59]0.003IMV (Yes)*2.45[-1.03, 3.87] < 0.001Quartile ICU stay 0–25%*1.64[0.67, 2.62] < 0.001 25–50%*1.86[1.02, 2.71] < 0.001 50–75%*1.17[0.41, 1.93]0.002Dyspnea(Intercept)0.69[0.03, 1.34]0.039IMV (Yes)*1.24[0.40, 2.08]0.003Quartile ICU stay 0–25%*1.24[0.45, 2.03]0.002 25–50%*0.9[0.21, 1.58]0.01 50–75% *0.81[0.19, 1.42]0.01Pain(Intercept)3.12[0.93, 5.30]0.005Age− 0.03[-0.07, 0.00]0.059Quartile ICU stay 0–25%*1.08[0.20, 1.95]0.016 25–50%1.04[0.25, 1.84]0.010 50–75%0.68[− 0.03, 1.40]0.061Data are presented as coefficient estimates, 95% confidence intervals, and p-values derived from mixed-effects models. Random intercepts were included to account for within-subject variability.IMV invasive mechanical ventilation, ICU intensive care unit.() p value < 0.05.Fig. 2Evolution of the levels of anxiety, sadness, dyspnea and pain during ICU stay by significant demographic and clinical factors. (A) Estimated level of anxiety during ICU stay by sex (left) and cause of admission (right), (B) Estimated level of sadness during ICU stay by IMV, (C) Estimated level of dyspnea during ICU stay by IMV. IMV = Invasive Mechanical Ventilation
Gender, cause of admission and ICU stay quartile were included as covariates in the multivariate model for anxiety. Male patients showed significantly lower anxiety levels than females, with an average reduction of 1.34 points (p = 0.039). When analyzing the progression of anxiety levels, using the final quartile of ICU stay as a reference, a significant increase was observed only in the second quartile, with a mean difference of 0.88 points (p = 0.026). Additionally, patients admitted for infection/respiratory conditions or sepsis exhibited significantly lower anxiety levels than those admitted for other causes, with reductions of 1.94 points (p = 0.021) and 1.83 points (p = 0.033) respectively (see Fig. 2A).
Invasive mechanical ventilation (IMV), deep sedation and ICU stay quartile were found to be significant in the univariate mixed-effects model for sadness. Sadness levels were significantly higher among patients who received IMV, with an average increase of 2.45 points (p < 0.001) in relation to those did not. Compared to the final quartile, sadness levels were significantly elevated during the first three ICU stay quartiles, with increases of 1.64 points (p < 0.001) in the first quartile (0–25% of stay), 1.86 points (p < 0.001) in the second (25–50%), and 1.17 points (p = 0.002) in the third (50–75%) (see Fig. 2B). Given the complete overlap between IMV and the administration of deep sedation (see Table S3), deep sedation was excluded from the multivariate model for sadness due to collinearity concerns.
IMV and ICU stay quartile were found to be significant in the univariate mixed-effects model for dyspnea. IMV was associated with an increase in dyspnea of 1.24 points (p = 0.003) in the multivariate model. Dyspnea levels fell at the end of the ICU stay, with significantly higher levels in the first three quartiles than in the final one; however, over the first three quartiles it rose by 1.24 points (first quartile, p = 0.002), 0.9 points (second, p = 0.01), and 0.81 points (third, p = 0.01) (see Fig. 2C).
In the univariate analysis, ICU stay quartile was the only variable significantly associated with pain, whereas age displayed a non-significant trend. In the multivariate model, pain was most intense during the earlier stages of the ICU stay, particularly in the first two quartiles, with increases of 1.08 points (p = 0.016) and 1.04 points (p = 0.010) respectively. The third quartile showed no significant effect (p = 0.061). Older age showed a slight, though non-significant, protective effect on pain levels, with a fall of 0.03 points per year (p = 0.059).
Spearman correlation analysis revealed a dynamic evolution in the relationships between anxiety, sadness, dyspnea and pain across the different phases of ICU stay (Fig. S1). Interestingly, the correlation between anxiety and sadness persisted across all quartiles, peaking in the last quartile (r = 0.55, p < 0.001).
During the first ICU phase, sadness exhibited a moderate correlation with pain (r = 0.44, p = 0.016) and a strong correlation with anxiety (r = 0.52, p = 0.002), while its association with dyspnea was weaker (r = 0.27). In the second quartile, the correlation between sadness and dyspnea became more pronounced (r = 0.46, p < 0.001), and sadness continued to show moderate correlations with anxiety (r = 0.39, p = 0.008).
Sadness maintained a strong correlation with dyspnea in the third quartile (r = 0.41, p < 0.001), which then decreased slightly in the last quartile (r = 0.25, p = 0.014). The relationship between sadness and pain was significant only in the first quartile and was not observed in subsequent ICU phases.
The correlation between dyspnea and pain varied across time, showing significant associations in the second quartile (r = 0.54, p < 0.001) and in the last phase of the ICU stay (r = 0.34, p = 0.004). In contrast, pain exhibited non-significant correlations with anxiety throughout the ICU stay.
At ICU discharge, the MoCA test revealed that 70.9% of patients (n = 59) had mild to moderate cognitive impairment. Comparisons between patients with normal cognitive performance and those with cognitive impairment were conducted using the Mann–Whitney U for continuous variables, and the Chi-square test for categorical variables. No statistically significant differences were found between the groups in terms of age, gender distribution, presence of delirium, need for IMV, or total hospital length of stay (see Table 3).Table 3Patient characteristics according to cognitive status stratified by MoCA test at ICU discharge.VariableNormal MoCA Score at ICU dischargeCognitive impairment at ICU dischargep valuen1544Age (yr), median [IQR]56.37 [47.26, 64.49]64.42 [50.74, 71.67]0.139Male, n (%)10 (66.7)27 (61.4)0.954Level of education, n (%)0.238 Mandatory4 (26.7)20 (45.5) Higher Education11 (73.3)24 (54.5)Cause of ICU admission, n (%)0.967 Cardiac3 (20.0)6 (13.6) Infection/respiratory3 (20.0)11 (25.0) Sepsis4 (26.7)13 (29.5) Trauma1 (6.7)3 (6.8)Other clinical conditions (Surgical complications, diabetic ketoacidosis, –gunshot wound, intestinal perforation, hemorrhagic shock)4 (26.7)11 (25.0)Charlson comorbidity index, median [IQR])2.00 [0.00, 4.00]3.00 [0.75, 4.00]0.547APACHE II, median [IQR]8.50 [6.25, 17.25]10.00 [8.00, 14.00]0.513Length of ICU stay (days), median [IQR]5.00 [2.50, 8.50]5.00 [3.00, 12.00]0.512Deep sedation (days), median [IQR]0.00 [0.00, 2.50]0.00 [0.00, 4.00]0.518Need for deep sedation, n (%)6 (40.0)21 (47.7)0.827Presence of delirium, n (%)1 (6.7)10 (22.7)0.259Need of IMV, n (%)6 (40.0)19 (43.2)1.000Tracheostomy*, n (%)0 (0.0)4 (9.1)0.564Duration of IMV (days)*, median [IQR]4.00 [3.00, 5.75]6.00 [3.00, 11.00]0.501Numbers are presented as n (%) for categorical variables and median [IQR] for continuous variables. Group comparisons were performed using the Kruskal–Wallis test for continuous variables and the Chi-square or Fisher test for categorical variables.*Data from patients who underwent IMV.IMV invasive mechanical ventilation, IQR interquartile range, ICU intensive care unit.
The presence of cognitive impairment at ICU discharge was not significantly related to the trajectories of anxiety (Estimate = 0.467; 95%CI = − 1.072, 2.006; p = 0.545), sadness (E = 0.656; 95%CI = − 1.111, 2.423; p = 0.459), dyspnea (E = 0.724; 95%CI = − 0.339, 1.788: p = 0.177), or pain (E = 0.093; 95%CI = − 1.347, 1.534; p = 0.897).
The current study explored the trajectories of emotional and physical distress among critically ill patients during their ICU stay and its association with cognitive status at ICU discharge. Consistent with previous findings on emotional distress^3,52^, 32.7 to 42.8% of our sample experienced moderate-to-severe levels of anxiety and 34.6 to 45.71% of sadness during ICU. Our results also indicated relative stability of the anxiety and sadness levels throughout the ICU stay, with a clinically relevant fall observed toward the end of the stay. This pattern aligns with prior research identifying anxiety and depressive symptoms as both highly prevalent and persistent among critically ill patients^1,2^. Despite some discordant results^2,14^, our findings support those of previous authors (1) who have stressed the higher levels of sadness compared to anxiety across all phases of the ICU stay. Although symptoms of anxiety and depression may present comorbidities in critically ill patients^14^, clinically, these results draw attention to a potential gap in current assessment practices, which typically rely on general inquiries into emotional well-being and rarely incorporate targeted evaluations of sadness or tearfulness. These findings highlight the importance of identifying periods of increased emotional and physical distress during ICU stay, as this may help clinicians anticipate vulnerability and consider timely supportive strategies when feasible.
In our study, around 20% of the sample experienced moderate to severe dyspnea, particularly during the first two-quartiles of the ICU stay. Dyspnea levels were notably higher in patients receiving IMV, with the symptom trajectory showing a transient increase during the third phase of the stay, followed by a fall prior to discharge. Although the reported prevalence rates of dyspnea in critically ill patients vary between studies, the temporal pattern observed in our cohort partially aligns with previous findings underlining the high prevalence and clinical relevance of dyspnea in these patients, especially among those requiring ventilatory support^53,54^. Variability in dyspnea reporting across studies may reflect differences in assessment tools, sedation protocols, or in patients’ ability to communicate. In fact, the slight increase in the level of dyspnea in our sample during the penultimate phase of admission could be attributed to the fact that in many intubated patients sedation is reduced during the transition phase, allowing them to perceive and report their feeling of breathlessness more accurately towards the middle of their ICU stay. In any case, these findings underscore the clinical importance of systematically assessing dyspnea throughout the ICU stay in order to address patient discomfort more effectively and guide clinical management.
In our study, pain levels during the ICU stay were notably low, with approximately 80 to 90% of patients reporting mild levels in the early phases of admission and very low pain or none at all in the final stages. Overall, pain levels remained minimal throughout the ICU stay, with a modest peak in the initial period followed by a decline afterward. These findings contrast with previous reports stating that 40% to 70% of ICU patients experience moderate to severe pain during their admission^29,31^. This discrepancy may be attributed to variations in the type of ICU (e.g., medical, surgical, etc.) or to differences in pain assessment and management protocols across institutions. In the study sample, the percentage of patients with potentially more painful diagnoses such as trauma and surgery was low, and pain management was routinely performed by nursing staff every two hours for all patients.
Emotional states during critical illness are known to be significantly influenced by the multitude of stressors inherent to the ICU environment, including sleep deprivation, dyspnea, pain, and delirium^4,40^. In this cohort, female patients reported significantly higher perceived levels of anxiety during their ICU stay, particularly during the intermediate phases of admission. This observation is consistent with previous reports suggesting potential differences in emotional responses between men and women in critical care settings (Cardoso et al., 2010; Wang et al., 2024), likely due to biopsychosocial factors that include differences in emotional coping mechanisms and perceived social support^11,14^. Furthermore, women have been reported to exhibit higher rates of anxiety symptoms following traumatic or highly stressful events^55^. From a psycho-social point of view, women may experience a greater burden of domestic and work responsibilities, which could contribute to higher self-reported anxiety levels^56^, specifically when they find themselves in the role of the person being cared for. Finally, the impact on emotional state of the differential management observed in some medical procedures in women admitted to the ICU may also influence emotional responses^57^.
Another relevant finding of this study is the association between the reason for ICU admission and anxiety levels experienced during the stay. Specifically, patients admitted for respiratory infections or sepsis reported lower anxiety levels than those admitted for other causes such as gastrointestinal bleeding or post-surgical monitoring. This may be due to the frequent need for IMV and deep sedation in the treatment of respiratory infections or sepsis, which reduces patients’ awareness of their clinical situation during the ICU stay. In contrast, patients admitted for other conditions that do not require IMV may remain more alert and conscious throughout their ICU stay, and experience greater psychological distress as a result. Furthermore, admission stemming from sudden or violent causes, such as trauma-related injuries (e.g., gunshot wounds), may elicit a particularly strong psychological impact and thus heighten anxiety levels.
Mechanical ventilation emerged as a risk factor for developing higher levels of sadness and dyspnea, but not anxiety, during the ICU stay. This association was particularly pronounced during the initial and intermediate phases of admission. These findings underline the pivotal role of IMV in contributing to physical and emotional distress, as documented in prior research^58,59^. They are also consistent with recent studies identifying IMV, particularly when accompanied by dyspnea, as a common physical stressor which interacts with the onset of emotional distress symptoms throughout the ICU stay^5,25,60^. No demographic or clinical factors were significantly associated with the development of pain during the ICU stay; however, and as previously reported^61^, a trend was observed toward higher levels of pain in younger patients. This pattern may be partially related to the nature of the underlying diagnoses that are more common among younger ICU patients, such as trauma or surgical interventions, which are typically associated with increased pain intensity.
As previously reported^14^, correlation analyses between emotional and physical stressors revealed a consistent and significant association between anxiety and sadness symptoms across all phases of the ICU stay. Sadness exhibited its strongest correlation with dyspnea during the mid and late phases of the stay, while its peak association with pain occurred in the early phase. Pain was also found to correlate with dyspnea during the middle and late phases. While pain may originate directly from specific clinical conditions or medical procedures, it can also interfere with respiratory function, thereby contributing to the perception of dyspnea even in the absence of ventilatory support. For example, in patients requiring IMV, both pain and dyspnea may be linked to extubation, tracheostomy and the shunting for throat injury or airway irritation. Despite this, in critically ill patients with thoracic trauma or digestive surgeries, postoperative pain from fractures or surgical wounds may affect their respiratory function and increase their perception of shortness of breath on inspiration. In any case, these patterns may reflect the emotional impact of the critical illness and its management, highlighting specific periods during the ICU stay, such as admission or the withdrawal of sedation and IMV, when the interplay between emotional and physical distress is particularly prominent. Notably, dyspnea and pain, both dimensions of physical discomfort, were more closely related to emotional manifestations of sadness than to anxiety. This pattern differs from those observed in previous reports, in which anxiety showed stronger associations with pain in the ICU^30^, although when depression symptoms are assessed a relation with pain has also been described^62^.
Finally, this study identified a high prevalence of cognitive impairment at ICU discharge, with nearly 80% of patients exhibiting mild to moderate deficits. Although these cognitive difficulties are likely transient, they may have important clinical implications during hospitalization, potentially affecting patients’ ability to comprehend or retain medical information, follow instructions, or adhere effectively to rehabilitation protocols (Andrews et al., 2023; Segernäs et al., 2022). This study did not identify any significant demographic or clinical predictors of cognitive performance, as assessed by the MoCA at ICU discharge. However, and in line with previous studies^39,63^, patients with worse cognitive scores showed a higher non-significant prevalence of delirium during their ICU stay. The lack of a significant association observed between cognitive difficulties at ICU discharge and levels of emotional and physical distress may suggest the presence of distinct mechanisms underpinning the development of cognitive versus emotional sequelae in critically ill survivors, though this interpretation should be considered with caution.
Several limitations of our study must be acknowledged. First, the relatively small sample size restricts the generalizability of our findings. Second, the clinical and demographic heterogeneity of our sample might have introduced variability that influenced the results; however, this heterogeneity accurately reflects the complexity of real-world ICU populations and may enhance the study’s external validity. Third, challenges in data collection posed another limitation; for instance, daily assessments of sadness, anxiety, dyspnea and pain were not feasible in patients experiencing delirium or under deep sedation. This may have led to underreporting of discomfort in some patients, particularly in relation to the detection of dyspnea in ventilated patients. Fourth, it was not possible to include information on participants’ previous emotional state, although having suffered from serious mental health illness prior to admission to the ICU was a reason for exclusion. Finally, patients were cognitively, but not emotionally, assessed at ICU discharge. Future research should explore alternative or longitudinal emotional and cognitive assessments to obtain a better understanding of the post-ICU outcomes. Qualitative research methodologies may be particularly valuable in exploring additional factors reported by patients in clinical settings that significantly impact their emotional for instance, the feeling of loneliness during hospitalization, or concerns related to being a primary caregiver or managing a business.
Our findings revealed a dynamic trajectory of anxiety, sadness, dyspnea, and pain over the course of the ICU stay, influenced by both demographic and clinical factors, in particular gender and the need for IMV. Although cognitive impairment was highly prevalent at ICU discharge, it did not show a significant association with demographic or clinical variables, nor with the trajectories of emotional and physical distress observed during the ICU stay. This study offers an innovative perspective on the complex interaction between the various dimensions of emotional distress in critically ill patients, highlighting the dynamic relationship between the different phases of the ICU stay. Therefore, for adequate detection of emotional distress in the ICU, it is advisable to adopt a multidimensional approach to the continuous psychological assessment carried out in the ICU setting, including conventional anxiety assessments but also incorporating questions about other affective states, such as sadness, the tendency to cry, emotional instability, and anger. Monitoring discomfort during the ICU stay will allow the detection of critical moments when early psychological interventions and specific symptom control measures could be beneficial, especially in patients requiring IMV.
Supplementary Information.