Title: The prevalence and course of post-traum...depression in children and adolescents
Author: Richard Delahaye (LLE - Staff)

A. Edwards et al.	Journal of Affective Disorders 405 (2026) 121601

Journal of Affective Disorders 405 (2026) 121601

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Journal of Affective Disorders
journal homepage: www.elsevier.com/locate/jad
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Research paper
The prevalence and course of post-traumatic depression in children and adolescents
Amber Edwards ^3’ , Eleanor Chatburn ^3’ , Richard Meiser-Stedman ^3
^a Department of Clinical Psychology & Psychological Therapies, Norwich Medical School, University of East Anglia, UK ^b Department of Public Health and Primary Care, University of Cambridge, UK

ARTICLE INFO

ABSTRACT

Keywords: Depression Youth
Trauma
Trajectory model
Symptom profiles

Background: The prevalence and course of depression following trauma is currently poorly understood within the literature, particularly in youth. Understanding the trajectory of depressive reactions post-trauma is critical for developing approaches to early management and treatment. This study considered the prevalence and trajectories of depression symptoms up to one-year post-trauma.
Method: Participants were 2006 trauma-exposed youth (mean age = 12.6 years; SD = 3.16) from the international PACT/R archive. Depression prevalence was assessed at four post-trauma intervals: acute (>24 h to 1 month), short (>1 to 3 months), intermediate (>3 to 6 months), and long-term (>6 to 12 months). Two operational definitions were used: “likely DSM-5 depression” (meeting DSM-5 diagnostic criteria) and “likely clinically significant depression” (based on frequently assessed symptoms). Prevalence of individual symptoms and symptom trajectories over time were analysed.
Results: The prevalence of “likely DSM-5 depression” was 18.5% in the acute phase and 14.8% at long-term follow-up. For “likely clinically significant depression”, rates were higher: 38.7% (acute) and 34.7% (longterm). Individual symptom prevalence ranged from 13.5% to 62.6% in the acute phase and 15.5% to 63.5% at long-term follow-up. Two symptom trajectories emerged: a smaller group (n = 165) with minimal symptoms and a larger group (n = 411) with persistent symptoms.
Conclusion: Depression is a common and often persistent response to trauma in children and adolescents, with limited spontaneous recovery over the first year. Routine screening and early intervention for depression in trauma-exposed youth are warranted. Further longitudinal research is needed to identify modifiable risk factors and effective treatment strategies.

Abbreviations: APA, American Psychological Association; ASD, acute stress disorder; CBT, cognitive behavioural therapy; DSM-5, Diagnostic and Statistical Manual of Mental Disorders 5; MDD, Major Depressive Disorder; PACT/R, Prospective Studies of Acute Child Trauma and Recovery; PTSD, post-traumatic stress disorder; WHO, World Health Organisation.
* Corresponding author at: University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK.
E-mail addresses: amber.edwards@uea.ac.uk, amber.edwards@cpft.nhs.uk (A. Edwards).
https://doi.Org/l0.1016/j.jad.2026.121601
Received 25 October 2025; Received in revised form 5 March 2026; Accepted 6 March 2026
Available online 9 March 2026
0165-0327/© 2026 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.0rg/licenses/by/4.0/).

1.		Introduction
1.1.		Depression in youth
Depression is a common mental health condition across youth. Depression is characterised by the absence of positive affect, low mood and irritability accompanied by symptoms such as changes in sleep, appetite and energy which impact an adolescent's functioning (American Psychological Association [APA], 2013). Depression is a leading cause of disability and illness among children and adolescents (World Health Organisation [WHO], 2024) and is associated with poor
long-term outcomes, including suicidality, social functioning problems, and both physical and mental health difficulties (Maughan et al., 2013). A recent meta-analysis (Lu et al., 2024) of adolescents across the globe identified major depression prevalence rates of 3.7% and prevalence of mild-severe depression symptoms of 21.3%. This analysis also noted that older youth have higher rates of depression, with a pooled prevalence rate of mild-severe depression symptoms of 27.4% in 10-18 year olds and a significantly lower prevalence of 7.1% in children under 10 years old. It is worth noting that there was very little data available for lower income countries and significant heterogeneity identified across studies, potentially highlighting the variation in methodology in assessing depression symptoms.
Depression in youth is a complex issue with multifactorial causes. The biopsychosocial model (Engel, 2012) provides a framework for understanding how different factors interact in the development of depression. Central to this model are factors such as early-life trauma, chronic stress, and genetic predispositions, all of which contribute to the onset of depression. Cognitive behavioural therapy (CBT) has been shown to be effective in the treatment of depression in children and adolescents (Garcia-Escalera et al., 2016); the CBT model (Beck et al., 1979) proposes that a person's early experiences may influence their core beliefs about themselves, malting them vulnerable to future depressive episodes. Thus, both the biopsychosocial and CBT models highlight the importance of early experiences, in shaping depressive responses. Shanahan et al. (2011) further reinforce this idea by identifying psychosocial risk factors, such as poverty and maltreatment, that are more strongly associated with childhood depression. These insights suggest that both early intervention and targeted support are crucial in mitigating the impacts of depression in youth.
1.2.		Trauma in youth
Exposure to potentially traumatic events is common among youth. Studies indicate that 61.8% of adolescents in the U.S. experience trauma by the age of 17 (McLaughlin et al., 2013). While the majority of youth demonstrate resilience, a significant proportion go on to develop psychological conditions, such as post-traumatic stress disorder (PTSD) and depression. PTSD is the most commonly studied response to trauma, but it is often accompanied by other mental health issues. Research has shown that PTSD and depression frequently co-occur, with up to 52% of PTSD cases involving comorbid depression (Rytwinski et al., 2013). The presence of depression symptoms negatively predicts PTSD psychotherapeutic treatment efficacy (Kline et al., 2021). Despite this, the natural recovery trajectories for depression following trauma, particularly in youth, are poorly understood, hindering the development of effective interventions for depression following a trauma.
1.3.		PTSD and depression
Depression is common in children and adolescents following trauma. A meta-analysis by Vibhakar et al. (2019) found that up to 24.2% of children and adolescents develop depression after a single traumatic event. Moreover, children who experience trauma are 2.6 times more likely to receive a diagnosis of depression compared to those who do not experience trauma. Trauma type also influences depression prevalence, with interpersonal violence linked to a higher rate of depression than other trauma types. These rates are higher than some found of PTSD, Elliott et al. (2021) found rates of PTSD ranged between 4.8 and 11.1%, dependent on the classification used (DSM-IV, DSM-5, ICD-10 or ICD- 11) in children and adolescents exposed to a single incident trauma. Trauma type has been shown to impact the prevalence of PTSD found in children and adolescents. A meta-analysis conducted by Alisic et al. (2014) found that prevalence rates of PTSD ranged between 8.4 and 13.3% if a trauma was not interpersonal, and that increased to 17.8 to 32.95% if a trauma was interpersonal. This reflects the impact of the severity and duration of trauma on symptoms.
Depression and PTSD share many overlapping risk factors, including being triggered by exposure to adverse life events and cognitive distortions (e.g. Afifi et al., 2009; Ehring et al., 2006; Spinhoven et al., 2014). The psychopathology of depression post-trauma remains unclear (Wang et al., 2023). It may emerge either as a direct consequence of the trauma or as a result of the ongoing distress caused by PTSD symptoms. PTSD has been found to be a risk factor for depression, conversely depression can increase vulnerability to PTSD and trauma exposure in women (Breslau et al., 1997). The interaction between these two conditions complicates diagnosis and treatment, which underscores the importance of exploring their comorbid trajectories. It may, therefore, be more useful to consider PTSD and depression as independent diagnoses, with shared risk factors.
Depression is likely involved in the development and maintenance of chronic PTSD. For instance, Meiser-Stedman et al. (2017) found that youth with acute stress disorder (ASD) who developed PTSD had more negative alterations in cognitions and mood after two weeks than those who did not develop PTSD. Clinically significant depression was found in a substantial minority of cases, though it was not predicted by ASD and showed little natural recovery.
1.4.		Trajectories of PTSD and depression
The recovery trajectories for PTSD have been comprehensively explored across different age groups. Bonanno (2004) identified four primary recovery trajectories: chronic, delayed, recovery, and resilient. Greene et al. (2017), in their latent class growth analysis of PTSD trajectories, found resilience to be the most common trajectory (65.7%), followed by recovery (20.8%), chronicity (10.6%), and delayed onset (8.9%). This data suggests that approximately half of individuals with PTSD symptoms experience spontaneous recovery. These findings were replicated in a study of children and adolescents by Hiller et al. (2016). They showed that PTSD prevalence decreases by around 50% between 1- and 6-months post-trauma, with little spontaneous recovery occurring after this period.
While PTSD recovery trajectories have been well documented, the trajectory of depression following trauma remains less understood, particularly in children and adolescents. Unlike PTSD, which is often associated with re-experiencing, and physical reactivity (APA, 2013), depression may have distinct pathways of onset, persistence, and resolution post-trauma (Wang et al., 2023); understanding the trajectory of depressive reactions post-trauma is critical for developing appropriate approaches to early management and treatment.
This gap in understanding is particularly critical because depression, unlike PTSD, might follow a more chronic and less spontaneous recovery trajectory. Preliminary research by Zhang et al. (2022) on depression trajectories post-trauma found that high levels of depression were persistent for up to 9 months following trauma, with PTSD and depression often occurring synchronously. However, those presenting with PTSD were moved into treatment, which means that we have little information on the depression symptoms of those who were presenting with PTSD. It is unclear whether similar trajectories would be observed in those with high PTSD symptoms but no intervention. Based on current evidence, it can be hypothesized that post-traumatic depression may follow a chronic trajectory, with significantly less spontaneous recovery compared to PTSD.
Understanding the trajectory of depression following trauma is essential for developing targeted, disorder-specific interventions. Given the potential for chronic symptoms, as hypothesized, this study aimed to illuminate both the course of post-traumatic depression and its symptomatology, providing critical insights for clinicians to improve longterm outcomes for affected youth. In particular, this study aimed to:
1.		Examine the natural recovery trajectories of depression in children and adolescents following single-incident trauma.
2.		Investigate the prevalence and severity of post traumatic depression and the individual symptoms of depression within the first-year posttrauma.
2.		Method
2.1.		Design
The present study involved pooling individual participant data from several previously published prospective longitudinal studies of trauma- exposed children and adolescents, in order to study the course of depression following a potentially traumatic event.
Data was drawn from an international archive - the Prospective Studies of Acute Child Trauma and Recovery (PACT/R) Data Archive, described in detail below (Kassam-Adams et al., 2020). The present study considered the presence of symptoms of depression, as defined within the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5; American Psychiatric Association, 2013), as well as plotting the trajectories of depression symptoms.
The PACT/R database has previously been utilised to study acute stress disorder and post-traumatic stress symptoms (Kassam-Adams et al., 2012, 2020). These studies included children with similar demographics, however, would have included additional datasets which did not measure depression, and which would have therefore been excluded from the present study. Within the database, 10.5% of the children studied were experiencing acute stress symptoms which met the DSM-5 criteria (Kassam-Adams et al., 2012) and 23.5% reported significant post-traumatic stress symptoms <1 month post trauma (Kassam-Adams et al., 2020).
2.2.		Data archive
This study utilised individual participant data included in the PACT/ R Data Archive (Kassam-Adams et al., 2020). This archive was formed to address limitations of small sample sizes and variety of measures used across child and adolescent trauma research, such as the ability to generalise findings and make cross-study comparisons. It is an international collaborative effort to bring datasets together in a common format. This archive currently includes data from five countries which was accessed for use in this study in June 2022. Within the data accessed there was a large range of measures of depression (Supplementary material A).
Datasets included in PACT/R comprise participants who were children and adolescents at the time of enrolment in the study. They were identified based on exposure to an acute, potentially traumatic event and not comprising treatment-seeking youth. The most common trauma types identified in these studies were disaster, injury, road traffic accidents, interpersonal violence and acute illness.
Data Inclusion: The criteria for inclusion in the present study were: children and adolescents aged 7-18 at enrolment, with data collected prospectively at a minimum of two timepoints beginning within six months of a traumatic event. For this research study we requested datasets which included measures of depression alongside trauma measures.
Data Exclusion: Studies where depression symptoms were only measured within 24 h of a potentially traumatic event were excluded. Studies which used a measure of depression which looked at less than five depression symptoms aligning with the DSM-5 criteria for depression (e.g. the Children's Depression Inventory, Short Form) were excluded. Adolescents were excluded if they were > 18 years old at enrolment.
2.3.		Ethical considerations
All data included in this study has required local ethical approval for inclusion in the PACT/R data archive. All data are deidentified and anonymised before being added to the database. At the time this study was conducted, the University of East Anglia's policy did not require separate ethical approval for the use of secondary data that had already received prior ethical clearance.
The Institutional Review Board (IRB) of The Children's Hospital of Philadelphia determined that the operation of the archive does not constitute human subjects research because all data are deidentified (Kassam-Adams et al., 2020).
The PACT/R database is accessed through application to the Child Trauma Data Archives and is overseen by the team at the University of Philadelphia, who ensure that the data is sent to researchers using it in line with the intended purpose.
Access to the data is agreed by a steering group prior to the data becoming available to the researcher to ensure the proposed study is in line with the ethical approval. Researchers for this study were granted consent to use the database on 17th June 2022. The present study was preregistered with the Open Science Framework (OFS) on the 23rd January 2024 (doi:10.17605/OSF.IO/UFSD7).
2.4.		Participants
Thirteen datasets from four countries from the dataset were identified as meeting the criteria of the present study. The pooled dataset incorporated a total of 2006 participants aged 7-18 (mean age 12.56 ± 3.16) The demographics of participants are outlined in Table 1.
2.5.		Defining depression
To understand the trajectories of depression symptoms, two definitions of ‘depression’ were used in the present study. These definitions stem from issues that arose in constructing our dataset. First, the majority of depression measures used did not include questions which captured all nine of the symptoms outlined by the DSM-5 criteria for Major Depressive Disorder (MDD). Second, the depression symptoms addressed by each measure did not necessarily overlap with other measures.
The inconsistency in the measurement of depression symptoms across the dataset highlights a significant challenge in defining depression within this research. As the present study seeks to understand the prevalence and trajectories of depression, we used two definitions of depression. ‘Likely DSM-5 Depression’ within this study was defined as the child indicating they have five out of the nine symptoms of depression outlined by the DSM-5, with at least one of these being depressed mood or loss of interest/pleasure in doing things. Impaired functioning related to these symptoms was not included within this definition, as this was not consistently measured within our dataset. While this definition best represented the full symptom range of the DSM-5 diagnosis of MDD, it also involved a high threshold as some measures did not index all nine symptoms. This definition therefore represents a more conservative approach. Due to the lack of congruence between the DSM-5 MDD definition and the symptoms considered within these measures, we also used a definition of ‘likely clinically significant depression’. This was defined as the presence of at least three of the five most measured symptoms within the dataset. These
Table 1
Descriptive statistics.
Variable | | Frequency | %
Country | USA | 1211 | 62.1
| UK | 426 | 21.8
| Australia | 135 | 6.9
| Switzerland | 180 | 9.2
Age | 7-10 | 507 | 26.0
| 11-15 | 1022 | 52.4
| 16-18 | 422 | 21.6
Gender | Male | 1215 | 62.2
| Female | 738 | 37.8
Race | White | 909 | 46.6
| Black | 430 | 22.7
| Asian | 38 | 2.0
| Mixed | 60 | 3.2
| Other | 455 | 24.0
| Not stated | 30 | 1.5
Trauma type | Unintentional injury | 1220 | 62.5
| Acute medical event (non-injury) | 106 | 5.4
| Motor vehicle/road traffic accident | 433 | 22.1
| Interpersonal violence | 163 | 8.3
| Other | 27 | 1.4
| Not stated | 2 | 0.1
symptoms were: i) depressed mood, ii) diminished interest, iii) fatigue, iv) worthlessness and v) decreased concentration.
Depressed mood is defined within the DSM-5 as being a feeling of low mood, hopelessness or irritability in adolescents. These symptoms are therefore combined within this work to reflect at whether ‘depressed mood' is present; this operationalisation was used for both the ‘likely DSM-5 Depression' and ‘likely clinically significant depression' definitions of depression. The presence of each of these individual symptoms is also reported.
A symptom was defined as present if a child or adolescent had experienced the symptoms ‘sometimes’ or more frequently. A child or adolescent was considered not to have the symptom if they reported experiencing it ‘never’ or ‘rarely'.
In order to combine data on specific symptoms, we used the methodology highlighted by Kassam-Adams et al. (2012), who used this archive to study acute stress symptoms in children. The symptoms in each measure were matched to congruent items on the DSM-5 for MDD. Consensus on the matching of the measures was completed by the PACT steering group.
The data was dichotomised using the individual measures standard scoring rules for symptom presence and harmonised to map to the DSM- 5 criteria for MDD in children and adolescents.
2.6.		Statistical analyses
Symptom and diagnoses counts, and their associated frequency statistics, were derived using SPSS version 28 (IBM corp, 2021). Data was calculated for four time windows: acute (>24 h to 1 month); short (>1 month to 3 months); intermediate (>3 months to 6 months); and longterm (>6 months - 12 months). Given that this study utilised data from research with diverse methodologies, it was believed that frequency statistics alone would not adequately account for the heterogeneity across the studies included in the dataset.
Random effects meta-analysis was therefore conducted in R version 4.4.2 (R Core Team, 2021) using the statistical package metafor (Viechtbauer, 2010) to derive prevalence estimates for each of the individual symptoms and each diagnosis within each time window.
2.7.		Trajectory modelling
To understand the trajectories of depression for children and adolescents exposed to a potentially traumatic event, group based trajectory modelling was conducted and mapped using the statistical package crimcv (2003 package; Nielsen et al., 2014) in R. Trajectories were mapped with studies which measured depression symptoms in three of our time windows: acute, short and long-term; these were selected as there was comparatively few data points for the intermediate time window. The model which had the lowest Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) values was identified to select the optimal trajectory model. AIC and BIC are measures of fit and complexity, with lower numbers indicating a better fit. As few of the studies included within the PACT/R dataset measured all nine symptoms of depression outlined by the DSM-5, trajectory modelling was completed using the five most measured symptoms included within ‘likely clinically significant depression' to maximise the dataset. These symptoms were: i) depressed mood, ii) diminished interest, iii) fatigue, iv) worthlessness and v) decreased concentration. Graphs to represent this trajectory were plotted using the statistical package ggplot2 in R (2024 package; Wickham, 2016).
3.		Results
3.1.		What is the prevalence and course of depression post-trauma?
For ‘likely DSM-5 depression' (i.e. five or more symptoms of depression) the threshold was met by 18.5% of children and adolescents within the acute period and this increased within the short time period, gradually decreasing to 14.8% in the long-term time windows (see Table 2). A very similar pattern was seen within the meta-analysis of the same data. The acute and long-term windows reflected the majority of studies (k = 9) and larger samples than the short and intermediate time frames. The ‘likely DSM-5 depression’ threshold was met by 22.2% of children and adolescents in the acute period (95% CI 15.1-30.3%) and 18.7% (95% CI 9.9-29.5%) in the long-term time window.
For the ‘likely clinically significant depression’ threshold, a similar pattern was seen with a higher prevalence. The presence of three or more symptoms of depression was reported by 38.7% in the acute window, decreasing slightly to 34.7% in the long-term window. The meta-analysis of this definition reflects an even higher proportion of children and adolescents experiencing such symptoms, with 49.2% prevalence within the acute period, reducing to 41.8% within the longterm window.
A similar pattern was found almost universally across individual depression symptoms, with the prevalence rates increasing in the short and intermediate windows (where there was less data available). This subsequently reduced in the long-term window to a prevalence slightly lower than that experienced within the acute window. Depressed mood (in particular depressed feelings and hopelessness), diminished interest in activities and worthlessness were the most commonly endorsed symptoms, while psychomotor agitation or retardation and thoughts of death or suicide were the least commonly endorsed. See Table 2 for the prevalence rates and meta-analysis of each individual symptom at each time point.
3.2.		What are the trajectories of depression symptoms following a trauma?
Five hundred and seventy-six children and adolescents had completed measures of their depression symptoms across the acute, short, and long-term time windows. Trajectory modelling of the symptoms i) depressed mood, ii) diminished interest, iii) fatigue, iv) worthlessness and v) decreased concentration was completed utilising this data. The model with the lowest AIC and BIC values was identified as the two-group model (Table 3). The best fit model was identified as being the two-group model (Fig. 1). This was the model with the lowest AIC and BIC values.
Trajectory group one reflected a ‘no symptoms present' trajectory. This comprised 165 (28.6% of the sample) children and adolescents. The majority of these participants had less than one of the measured depression symptoms within the acute period following a trauma and this was sustained within the year following trauma. Trajectory group two reflected a persistent ‘symptoms present’ trajectory of children and young people who persistently had some symptoms - ranging widely from 1 to 5 out of the 5 most measured symptoms of depression, with an average of 3 symptoms present - in the year post-trauma. This encompassed 411 children and adolescents (71.4%).
4.		Discussion
4.1.		Summary of findings
This study used a pooled dataset of trauma-exposed children and adolescents to begin to understand the prevalence and trajectories of depression symptoms following a trauma. The prevalence rates of depression across definitions and individual symptoms were reflective of a chronic trajectory for a significant proportion of cases. The most commonly reported symptoms were depressed mood (62.6% in the acute-, 64.6% in the short-, 51.2% in the intermediate-, 63.5% in in the long-term window), worthlessness (61.6% in the acute-, 62.1% in the short-, 50.5% in the intermediate-, 58.3% in in the long-term window) and diminished interest (50.7% in the acute-, 51.2% in the short-, 51.5% in the intermediate-, 54.5% in in the long-term window). Only two
Table 2
Prevalence of depression diagnoses and symptoms, using raw proportions and meta-analysis estimates.
| Acute >24 h-1 month | Short >1-3 months | Intermediate >3-6 months | Long term >6-12 months

Likely DSM-5 depression

Raw proportion
Meta-analysis

18.5% (290/1568)
22.2%
(9, 15.1-30.3%)

25.0% (159/637)
28.8%
(5, 14.6-45.5%)

20.9% (103/493)
19.8%
(3, 7.3-36.4%)

14.8% (131/884)
18.7%
(9, 9.9-29.5%)

Likely clinically significant depression

Raw proportion
Meta-analysis

38.7% (606/1567)
49.2%
(9, 27.8-70.7)

57.9% (319/551)
72.1%
(5, 36.1-961.6)

47.1% (232/493)
49.3%
(3, 13.0-86.0%)

34.7% (307/884)
41.8%
(9, 24.9-59.8%)

Depressed mood^c

Raw proportion
Meta-analysis

62.6% (980/1566)
66.9%
(9, 46.2-84.7)

64.6% (356/551)
72.0%
(5, 42.6-93.6%)

51.2% (252/492)
57.2%
(3, 11.6-95.9%)

63.5% (561/883)
59.5%
(9, 37.3-79.8)

Depressed feeling

Raw proportion
Meta-analysis

47.7% (741/1554)
41.1%
(8, 21.0-62.9)

58.4% (321/550)
59.7%
(5, 24.2-90.1)

42.5% (209/492)
41.4%
(3, 0.4-94.4%)

51.6% (455/881)
49.7%
(9, 17.4-82.0%)

Hopelessness

Raw proportion
Meta-analysis

58.6% (576/983) 49%
(5, 18.0-80.5%)

47.5% (151/318)
44.9%
(4, 9.2-84.1%)

56.3% (153/272)
51.6%
(2, 5.8-95.6%)

53.3% (328/615)
32.7%
(6, 11.2-59.1%)

Irritability

Raw proportion
Meta-analysis

42.8% (415/970)
31.2%
(5, 20.4-43.1%)

33.1% (81/245)
35.1%
(3, 21.0-50.7%)

26.6% (72/271)
26.8%
(2, 20.0-34.2%)

52.2%
(319/611)
44%
(6, 14.2-76.5%)

Diminished interest

Raw proportion
Meta-analysis

50.7% (677/1335)
56.5%
(8, 34.3-77.4%)

51.2% (282/551)
67.1%
(5, 26.9-96.2%)

51.5% (253/491)
56.7%
(3, 15.3-93.0%)

54.5%
(390/715)
67%
(9, 0.37.6-90.5%)

Appetite

Raw proportion
Meta-analysis

27.2% (301/1106)
35.4%
(8, 18.9-54.0%)

36.5% (115/315)
37.8%
(4, 17.9-60.1%)

23.2%
(114/491)
23.9%
(3, 15.9-32.8%)

22.5% (125/555)
23.7%
(8, 12.2-37.6%)

Insomnia or hypersomnia

Raw proportion
Meta-analysis

40.2% (447/1112)
42.9%
(8, 34.5-51.5%)

34.6% (110/318)
34.6%
(4, 29.4-39.9%)

33.9%
(166/489)
30.4%
(3. 15.6-47.5%)

29.0% (161/555)
29.1%
(8, 18.8-40.7%)

Psychomotor agitation or retardation

Raw proportion
Meta-analysis

25.5% (147/576)
17.1%
(3, 6.1-32.3%)

32.0% (108/338)
30.4%
(2, 20.7-41.0%)

18.0% (68/378)
18.4%
(2, 7.6-32.7%)

15.5% (41/264)
16.1%
(2, 6.2-29.6)

Fatigue

Raw proportion
Meta-analysis

33.4% (363/1088)
34.7%
(6, 19.1-52.2%)

46.2% (241/521)
45.0%
(5, 35.4-54.7%)

43.4% (213/491)
41.1%
(3, 27.8-55.1%)

31.1% (184/592)
32.8%
(7, 23.0-43.4%)

Worthlessness

Raw proportion
Meta-analysis

61.6% (964/1566)
57.6%
(9, 39.2-74.9%)

62.1% (342/551)
77.3%
(5, 46.7-97.0%)

50.5% (248/491)
61.9%
(3, 36.6-84.1%)

58.3% (515/884)
55.8%
(9, 32.5-77.8%)

Decreased concentration

Raw proportion
Meta-analysis

39.0% (467/1197)
38.8%
(7, 31.5-46.5%)

40.4% (205/507)
40.9%
(5, 36.1-45.7%)

28.6% (140/490)
28.4%
(3, 21.8-35.4%)

29.5% (168/570)
32.5%
(7, 23.4-42.2%)

Thoughts of death/suicide

Raw proportion
Meta-analysis

13.5% (109/807)
18.7%
(5, 7.8-32.9%)

11.1% (18/163)
10.1%
(2, 2.4-22.3%)

8.2% (18/219)
8.2%
(1, 5.0-12.2%)

17.6% (49/278)
15.7%
(5, 7.0-27.2%)

For proportion n/N are given in parentheses; for meta-analysis, k and 95% CI are given in parentheses.
a The child or young person indicated they have five out of the nine symptoms of depression outlined by the DSM-5, with at least one of these being i) depressed mood or ii) loss of interest or pleasure in doing things.
^b The presence of three of the five most measured symptoms of depression: depressed mood, diminished interest, fatigue, worthlessness and decreased concentration.
^c At least one symptom of depressed mood present, encapsulating symptoms of low mood, hopelessness or irritability as defined in the DSM-5 criteria for MDD.

symptoms showed evidence of recovery between these time windows: insomnia or hypersomnia and psychomotor agitation or retardation.
Prevalence rates varied between ‘likely DSM-5 depression’ (i.e. met five out of the nine symptoms of depression outlined by the DSM-5; 18.5% in the acute-, 25% in the short-, 20.9% in the intermediate-, 14.8% in in the long-term window) and ‘likely clinically significant depression’ (i.e. presence of three of the five most measured symptoms of depression; 38.7% in the acute-, 57.9% in the short-, 47.1 in the intermediate-, 41.8% in in the long-term window). This finding is likely related to the lack of measures used which incorporated all nine symptoms of the DMS-5 definition of depression. We were unable to address the full DSM-5 criteria for depression, due to the lack of data available on the impairment of these symptoms on functioning. The prevalence rate of depression symptoms within the acute period was higher (18.5%) than the prevalence of acute stress symptoms previously studying using this data archive (10.5%) (Kassam-Adams et al., 2012). We found similar levels of depression symptoms (14.8-25.0%) <1 month post trauma to significant post-traumatic stress (23.5%)

Table 3
Fit statistics for group-based trajectory models.
Number of groups | LogL" | AIC | BIC | CVE^b
1 | -2575.95 | 5159.89 | 5181.71 | 204.61
2 | 2426.79 | 4871.57 | 4920.66 | 204.14
3 | -2426.65 | 4881.30 | 4957.67 | 204.14
4 | -2575.00 | 5188.00 | 5291.64 | -
5 | -2426.65 | 4901.31 | 5032.22 | 205.34
6 | -2426.65 | 4991.30 | 5069.49 | 204.73
^a Log-likelihood: Used to compare the fit of different models. A higher loglikelihood indicates a better model fit.
^b Classification accuracy: Used to evaluate how well the model classifies individuals into their respective trajectory groups. It measures the proportion of individuals that are accurately assigned to the trajectory group they most likely belong to, based on their observed data.

symptoms as previously found using the PACT/R data archive. A significant minority of children and adolescents whose symptoms of trauma have been studied using the PACT/R archive experience depression or post-traumatic stress symptoms. However, the degree of comorbidity within this population, particularly over time, requires further exploration.
Two trajectories of depression were identified: a small proportion (n = 165) of children and adolescents did not experience depression symptoms, while the larger proportion (n = 411) experienced persistent symptoms. There was no late onset trajectory identified. In contrast to PTSD, no recovery trajectory was identified. Given the range of measures used across studies we could not ascertain trajectories for diagnostic-level depression, but the pattern of results suggest a lack of spontaneous recovery in depression symptoms experienced following a trauma.
4.2.		Clinical and theoretical implications
These findings reflect the importance of incorporating depression into our understanding of psychological responses to trauma. This is particularly pertinent given the high levels of trauma exposure in youth (61.8%; McLaughlin et al., 2013) and long-term impacts of depression on mental and physical health (Maughan et al., 2013). Attending to depression following a trauma also has the potential to increase the efficacy of other treatments, as greater depression severity has been found to reduce the efficacy of treatment for PTSD (β = -0.36) (Kline et al., 2021). Given that depression symptoms co-occur in 52% of PTSD cases (Rytwinski et al., 2013), this has significant clinical implications.
The majority of prevalence rates identified in this study far exceed the 21.3% prevalence rates of mild-severe depression found in children and adolescents globally (Lu et al., 2024). Prevalence rates of likely clinically significant depression in the year following a trauma were consistently higher than those we would expect to see in the general child and adolescent population. Our findings suggest that a significant proportion of children and adolescents who experience a traumatic experience develop symptoms of depression, and that these symptoms do not spontaneously recover. This reflects a need for active screening and treatment of depression symptoms following a trauma, so that clinically significant symptoms can be quickly identified, and indicates that delaying treatment is unlikely to be advantageous.

Fig. 1. Trajectory modelling of the five most measured symptoms of depression across the year following an acute trauma.

Current theoretical models of depression incorporate early experiences into the formulation of the maintenance of depression (Beck et al., 1979; Engel, 2012). However, we currently have little understanding of the factors which lead to post-traumatic depression as a stand-alone diagnosis, and what predisposes a child or adolescent to experience depression rather than another psychopathology.
Given our finding that symptoms of depression are likely to be persistent following a trauma for a significant proportion of youth, the development of specific models of depression following a trauma would aid formulation and recovery. Recent exploration into such models has highlighted that many of the cognitive factors linked to depression are also found in PTSD, Complex PTSD and anxiety following trauma (Memarzia et al., 2024). This suggests that such cognitive factors are consistent across diagnoses and require further exploration.
4.3.		Limitations and methodological issues
This research has several limitations. The main challenge was in defining the presence of depression itself, due to the large range of measures utilised. This reflects a wider problem within depression research with non-overlapping measures. Analysis of seven common depression scales found that only 12% of symptoms were present across all measures and the mean overlap among scales ranging from 0.27 to 0.40 (Fried, 2017). To mitigate this challenge two definitions of depression were presented, one which aligns closely to the DSM-5 criteria for depression and one which looks at the five most reported depression symptoms. These were designed to strike a balance between clinical definition and maximising the available data. Whether these children and adolescents would meet clinical criteria for depression is unclear due to the lack of information available on the impact of the symptoms experienced.
Another limitation of this study is the threshold for symptom presence. The DSM-5 outlines that for a diagnosis of depression symptoms must be present for at least 2 weeks. Therefore, if a child reported experiencing a symptom was experienced ‘sometimes' or more frequently it was considered as present within this study. This aligns with the diagnostic criteria utilised, however the severity of symptoms is not measured. Prevalence of symptoms therefore includes mild-severe symptoms and does not differentiate between these, potentially inflating symptom presence.
The majority of the measures used within this study measured symptoms over the last two weeks, as necessary for diagnosis in accordance with the DSM-5. However, the Birleson Depression Self-Rating Scale (Birleson, 1981; Birleson et al., 1987) and the Center for Epidemiological Studies Depression Scale for Children (Faulstich et al., 1986) looked at symptoms over the last week and therefore not all symptoms are measured across the same time scale.
In order to identify the trajectories of depression, participants were included who had completed measures at three timepoints were identified. In doing so, we were unable to incorporate data from the majority of participants. However, this was still a significant sample size. The trajectories identified are also consistent with the prevalence rates observed in the meta-analysis. The majority of our sample (η = 1759, 90%) included children and adolescents who had been exposed to trauma which was not interpersonal in nature, including unintentional injury (n = 1220, 62.5%), acute medical event (n = 106, 5.4%) and motor vehicle or road traffic accident (n = 433, 22.1%). A minority of our sample had been exposed to interpersonal violence (n = 163, 8.3%). Given our knowledge that trauma type increases the prevalence of PTSD (Alisic et al., 2014), it is probable that interpersonal violence impacts the prevalence of depression symptoms. Given the small percentage of our sample exposed to interpersonal violence we are unable to conclude the impact of this type of trauma on the prevalence of depression symptoms.
A further limitation of this research is the lack of pre-morbid information on the children and adolescents studied. We are therefore unable to attribute the symptoms of depression directly to the trauma as we cannot compare this to pre-traumatic symptoms.
4.4.		Further research and recommendations
Thus far, the course of post-traumatic depression in children and adolescents has been largely unconsidered. The understanding of the long-term impacts of depressive symptoms following a trauma is limited and as such the utility of our current theoretical models is not understood. Further research and the development of our understanding will allow us to create more effective treatments for this group. Such research would also support in understanding other psychopathologies, such as PTSD and complex PTSD and the interplay with depression symptoms. Further studies could also focus on the understanding of post- traumatic depression across developmental stages.
In order to characterise depression consistently within future research, validated measures of depression should be used in the study of psychological responses to trauma. These should be reflective of the current DSM or ICD definitions of depression, ensuring that they also incorporate the impact of such symptoms on functioning.
Given the large overlap between the DSM-5 criteria for PTSD and depression, we would anticipate that a portion of the sample would have overlapping symptoms of PTSD and other anxiety disorders, which may in part account for the symptoms of depressed mood within this sample. Further research could map the trajectories of these potentially overlapping psychopathologies.
5.		Conclusions
The present study brought together a large pre-existing data set incorporating children and adolescents who had been exposed to trauma. It has highlighted that depression is a common response to exposure to traumatic experiences and that symptoms of depression are unlikely to recover spontaneously. This finding indicates that a proactive approach to screening and treatment of depression is likely to improve clinical outcomes for those who have been exposed to a traumatic event.
Depression following a trauma is still largely understudied in the literature and is an area which requires urgent attention to understand the mechanisms underpinning it. Further research would support in the development of a robust model of post-traumatic depression in children. Such research should focus on increasing our understanding of depression following trauma and the relationship with other psychopathologies.
CRediT authorship contribution statement
Amber Edwards: Writing - review & editing, Writing - original draft, Project administration, Methodology, Formal analysis, Data curation, Conceptualization. Eleanor Chatburn: Writing - review & editing, Supervision, Conceptualization. Richard Meiser-Stedman: Writing - review & editing, Supervision, Methodology, Formal analysis, Conceptualization.
Declaration of competing interest
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Richard Meiser-Stedman reports a relationship with University of East Anglia that includes: speaking and lecture fees. Amber Edwards and Eleanor Chatburn declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The authors thank Nancy Kassam-Adams PhD, Leila Graham and other research team members of the PACT project at Children's Hospital of Philadelphia, for their support in accessing the data archive and providing guidance on preparing the data for analysis. We also acknowledge with gratitude all those researchers who shared their data with the archive.
Appendix A. Supplementary data
Supplementary data to this article can be found online at https://doi. org/10.1016/j.jad.2026.121601.
References
Afifi, Τ.Ο., Boman, J., Fleisher, W., Sareen, J., 2009. The relationship between child abuse, parental divorce, and lifetime mental disorders and suicidality in a nationally representative adult sample. Child Abuse Negl. 33 (3), 139-147. https://doi.org/ 10.1016/j.chiabu.2008.12.009.
Alisic, E., Zalta, Α.Κ., Van Wesel, F., Larsen, S.E., Hafstad, G.S., Hassanpour, Κ., Smid, G. E., 2014. Rates of post-traumatic stress disorder in trauma-exposed children and adolescents: meta-analysis. Br. J. Psychiatry 204 (5), 335-340. https://doi.org/ 10.1192/bjp.bp.113.131227.
American Psychiatric Association, 2013. Diagnostic and Statistical Manual of Mental Disorders, 5th ed. https://doi.org/10.1176/appi.books.9780890425596.
Beck, Α.Τ., Rush, A.J., Shaw, B.F., Emery, G., DeRubeis, R.J., Hollon, S.D., 1979. Cognitive Therapy of Depression. Guilford Publications.
Birleson, Ρ., 1981. The validity of depressive disorder in childhood and the development of a self-rating scale: a research report. J. Child Psychol. Psychiatry 22 (1), 73-88. https://doi.org/!0.1111/ j.1469-7610.1981.tb00533.x.
Birleson, P., Hudson, I., Grey-Buchanan, D., Wolff, S., 1987. Clinical evaluation of a selfrating scale for depressive disorder in childhood (depression self-rating scale). J. Child Psychol. Psychiatry 28, 43-60. https://doi.Org/10.llll/j.1469-7610.1987. tb00651.x.
Bonanno, G.A., 2004. Loss, trauma, and human resilience: have we underestimated the human capacity to thrive after extremely aversive events? Am. Psychol. 59 (1), 20-28.
Breslau, N., Davis, G.C., Peterson, E.L., Schultz, L., 1997. Psychiatric sequelae of posttraumatic stress disorder in women. Arch. Gen. Psychiatry 54 (1), 81-87. https://doi.org/10.1001/archpsyc.1997.01830130087016.
Ehring, T., Ehlers, A., Glucksman, Ε., 2006. Contribution of cognitive factors to the prediction of post-traumatic stress disorder, phobia and depression after motor vehicle accidents. Behav. Res. Ther. 44 (12), 1699-1716. https://doi.0rg/lO.lOl6/j. brat.2005.11.013.
Elliott, Rachel, McKinnon, Anna, Dixon, Clare, Boyle, Adrian, Murphy, Fionnuala, Dahm, Theresa, Travers-Hill, Emma, et al., 2021. Prevalence and predictive value of ICD-11 post-traumatic stress disorder and Complex PTSD diagnoses in children and adolescents exposed to a single-event trauma. J. Child Psychol. Psychiatry 62 (3), 270-276. https://doi.org/10.1111/jcpp.13240.
Engel, G.L., 2012. The need for a new medical model: a challenge for biomedicine. Psychodyn. Psychiatry 40, 377-396. United States: Guilford Press, https://d0i.0rg/l 0.I521/pdps.2012.40.3.377.
Faulstich, Μ.Ε., Carey, M.P., Ruggiero, L., et al., 1986. Assessment of depression in childhood and adolescence: an evaluation of the Center for Epidemiological Studies Depression Scale for children (CES-DC). Am. J. Psychiatry 143 (8), 1024-1027. https://doi.0rg/10.1176/ajp.143.8.1024.
Fried, E.I., 2017. The 52 symptoms of major depression: lack of content overlap among seven common depression scales. J. Affect. Disord. 208, 191-197. https://doi.org/ 10.1016/j.jad.2016.10.019.
Garcia-Escalera, J., Chorot, P., Valiente, R.M., Reales, J.M., Sandin, B., 2016. Efficacy of transdiagnostic cognitive-behavioral therapy for anxiety and depression in adults, children and adolescents: a meta-analysis. RPPC 21 (3), 147-175. https://doi.org/ 10.5944/rppc.vol.21.num.3.2016.17811.
Greene, T., Gelkopf, M., Grinapol, S., Werbeloff, N., Carlson, E., Lapid, L., 2017. Trajectories of traumatic stress symptoms during conflict: a latent class growth analysis. J. Affect. Disord. 220, 24-30. https://doi.org/10.1016/j-jad.2017.05.036.
Hiller, R.M., Halligan, S.L., Ariyanayagam, R., Dalgleish, T., Smith, P., Yule, W., Glucksman, E., Watson, P., Meiser-Stedman, R., 2016. Predictors of posttraumatic stress symptom trajectories in parents of children exposed to motor vehicle collisions. J. Pediatr. Psychol, https://doi.org/10.1093/jpepsy/jsv068.
IBM Corp, 2021. IBM SPSS Statistics for Windows, Version 28.0. IBM Corp., Armonk, NY.
Kassam-Adams, N., Palmieri, P.A., Rork, K., Delahanty, D.L., Kenardy, J., Kohser, K.L., Landolt, Μ.Α., Le Brocque, R., Marsac, M.L., Meiser-Stedman, R., Nixon, R.D.V., Bui, E., McGrath, C., 2012. Acute stress symptoms in children: results from an international data archive. J. Am. Acad. Child Adolesc. Psychiatry, https://doi.org/ 10.1016/j.jaac.2012.05.013.
Kassam-Adams, N., Kenardy, J., Delahanty, D., Marsac, M., Meiser-Stedman, R., Nixon, R.D.V., Landolt, M., Palmieri, P., 2020. Development of an international data repository and research resource: the Prospective studies of Acute Child Trauma and Recovery (PACT/R) Data Archive. Eur. J. Psychotraumatol. https://doi.org/ 10.1080/20008198.2020.1729025.
Kline, A.C., Cooper, Α.Α., Rytwinski, Ν.Κ., Feeny, N.C., 2021. The effect of concurrent depression on PTSD outcomes in trauma-focused psychotherapy: a meta-analysis of randomized controlled trials. Behav. Ther. 52 (1), 250-266. https://doi.org/ 10.1016/j.beth.2020.04.015.
Lu, B., Lin, L., Su, X., 2024. Global burden of depression or depressive symptoms in children and adolescents: a systematic review and meta-analysis. J. Affect. Disord. 354, 553-562. https://doi.Org/10.1016/j.jad.2024.03.074.
Maughan, B., Collishaw, S., Stringaris, A., 2013. Depression in childhood and adolescence. J. Can. Acad. Child Adolesc. Psychiatry 22 (1), 35-40.
McLaughlin, Κ.Α., Koenen, K.C., Hill, E.D., Petukhova, M., Sampson, Ν.Α., Zaslavsky, A. M., Kessler, R.C., 2013. Trauma exposure and posttraumatic stress disorder in a national sample of adolescents. J. Am. Acad. Child Adolesc. Psychiatry 52 (8), 815-830. https://doi.Org/10.1016/j.jaac.2013.05.011.
Meiser-Stedman, R., McKinnon, A., Dixon, C., Boyle, A., Smith, P., Dalgleish, T., 2017. Acute stress disorder and the transition to posttraumatic stress disorder in children and adolescents: prevalence, course, prognosis, diagnostic suitability, and risk markers. J. Depression Anxiety 34, 348-355. https://doi.org/10.1002/da.22602.
Memarzia, J., Lofthouse, K., Dalgleish, T., Boyle, A., McKinnon, A., Dixon, C., Smith, P., Meiser-Stedman, R., 2024. Predictive models of post-traumatic stress disorder, complex post-traumatic stress disorder, depression, and anxiety in children and adolescents following a single-event trauma. Psychol. Med. https://doi.org/ 10.1017/S0033291724001648.
Nielsen, J.D., Rosenthal, J.S., Sun, Y., Day, D.M., Bevc, I., Duchesne, T., 2014. Group- Based Criminal Trajectory Analysis Using Cross-Validation Criteria. Commun. Stat. Theory Methods, United States.
R Core Team, 2021. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/.
Rytwinski, Ν.Κ., Scur, M.D., Feeny, N.C., Youngstrom, E.A., 2013. The co-occurrence of major depressive disorder among individuals with posttraumatic stress disorder: a meta-analysis. J. Trauma. Stress. 26 (3), 299-309. https://doi.org/10.1002/ jts.21814.
Shanahan, L., Copeland, W.E., Costello, E.J., Angold, A., 2011. Child-, adolescent-, and young adult-onset depressions: differential risk factors in development? Psychol. Med. 41 (11), 2265-2274. https://doi.org/10.1017/S0033291711000675.
Spinhoven, P., Penninx, B.W., Van Hemert, A.M., De Rooij, M., Elzinga, B.M., 2014. Comorbidity of PTSD in anxiety and depressive disorders: prevalence and shared risk factors. Child Abuse Negl. 38 (8), 1320-1330. https://doi.0rg/lO.lOl6/j. chiabu.2014.01.017.
Vibhakar, V., Allen, L., Gee, B., Meiser-Stedman, R., 2019. A systematic review and metaanalysis on the prevalence of depression in children and adolescents after exposure to trauma. J. Affect. Disord. https://doi.Org/10.1016/j.jad.2019.05.005.
Viechtbauer, W., 2010. Conducting meta-analyses in R with the metafor package. J. Stat. Softw. 36 (3), 1-48. https://doi.org/10.18637/jss.v036.i03.
Wang, S.K., Feng, M., Fang, Y., Lv, L., Sun, G.L., Yang, S.L., Chen, Η.Χ., 2023. Psychological trauma, posttraumatic stress disorder and trauma-related depression: a mini-review. World J. Psychiatry 13 (6), 331. https://doi.org/10.5498/wjp.v13. i6.331.
Wickham, H., 2016. ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag, New York. ISBN 978-3-319-24277-4. https://ggplot2.tidyverse.org.
World Health Organization, 2024. Adolescent and Young Adult Health, https://www.wh o.int/news-room/fact-sheets/detail/adolescents-health-risks-and-solutions/ (Accessed on 05.02.2025).
Zhang, J., Meiser-Stedman, R., Jones, B., Smith, P., Dalgleish, T., Boyle, A., Edwards, A., Subramanyam, D., Dixon, C., Sinclaire-Harding, L., Schweizer, S., Newby, J., McKinnon, A., 2022. Trajectory of post-traumatic stress and depression among children and adolescents following single-incident trauma. Eur. J. Psychotraumatol. https://doi.org/10.1080/20008198.2022.2037906.