Post traumatic stress disorder (PTSD) is a mental health condition that can develop after someone experiences or witnesses frightening, upsetting and/or life-threatening events. This can manifest with flashbacks or nightmares, avoidance, feeling constantly on edge, negative thoughts or feelings, and trouble sleeping and/or concentrating (NICE, 2018).
PTSD in children and adolescents is a distressing and often long-lasting mental health condition which frequently co-occurs with other psychiatric disorders (Morina et al., 2016). Research suggests that over 7% of young people in the UK will experience PTSD by age 18 (Lewis et al., 2019).
Trauma-focused cognitive-behavioural therapies (TF-CBTs) are recommended as first-line treatments for PTSD (NICE, 2018) and we already know that this intervention works well for young people (Neelakantan et al., 2019). However, where symptoms are more complicated, there have been multiple traumatic stressors, and where additional symptoms such as depression, anxiety and anger occur, then there is less evidence on which therapies work well. This is clearly a problem; such clinical presentations are not uncommon, but can appear considerably more complex and risk becoming harder to treat, therefore, more evidence is needed in this area (Maercker et al., 2022).
Many studies evaluating TF-CBT lack pragmatic designs, meaning that they do not reflect real-world conditions, often recruiting young people from social service settings and not mental health services (Ascienzo et al., 2021). To address these issues and limitations, a recent randomised controlled trial, DECRYPT (Delivery of Cognitive Therapy for Young People after Trauma), examined the effectiveness of a specific type of TF-CBT, cognitive therapy for PTSD (CT-PTSD), among children and adolescents within UK Mental Health Sites who have experienced multiple traumatic events (Meiser-Stedman et al, 2025).
PTSD in young people is common and complex, and the DECRYPT trial questions whether structured cognitive therapy, known as CT-PTSD, can meet real-world needs.
Methods
The study compared two groups:
- One group received CT‑PTSD
- The other group received usual treatment (“treatment as usual” or TAU).
CT-PTSD involved up to 15 sessions focusing on psychoeducation, narrative work, imaginative reliving, cognitive restructuring, and coping strategies. Three sessions included working on any comorbid conditions. Treatment was delivered by CT-PTSD trained NHS practitioners.
TAU involved any form of treatment ordinarily offered in the service, notably including other types of trauma-focused CBT and medication changes. Therapy adherence was monitored through supervision by clinical psychologists and session recordings. All practitioners were asked to provide their reflections on their experience and therapies used.
The main measurement the study used was called the Child Revised Impact of Event Scale, 8‑item version (CRIES‑8), which measures trauma symptoms.
The study measured at “post-treatment” (around 5-6 months after randomisation) and at 11 months later.
Researchers hypothesised that CT-PTSD would be better than TAU across several outcomes: PTSD severity, complex PTSD symptoms, anxiety, depression, overall functioning, and parent-rated mental health.
Results
The DECRYPT trial tested CT-PTSD among children and adolescents with PTSD from multiple traumas. In total, 120 young people (aged 8-17) with PTSD following multiple traumatic stressors were randomised: 58 to the Cognitive Therapy for PTSD (CT‑PTSD) arm and 62 to the Treatment‑as‑Usual (TAU) arm.
The participants all had been exposed to multiple traumatic stressors and were recruited from six UK NHS Child and Adolescent Mental Health Services (CAMHS).
The sample was predominantly female (72.5%), with a mean age of 14.9 years. On average, participants reported 14 traumatic events and 4.7 trauma types. Over half (55%) met diagnostic criteria for complex PTSD using ICD-11; furthermore, 74% screened positive for depression, and 51% for anxiety, indicating a highly comorbid and severely affected group at baseline.
Primary outcome
Right after treatment completed (at the first measurement – around 5-6 months after randomisation), CT-PTSD did not show a statistically significant improvement over TAU on the main CRIES-8 measure when they included all participants. The difference was small, and the p-value was 0.095.
However, of note, as mentioned, TAU could include other forms of TF-CBT. When the research team excluded those participants in the TAU group who had already received a trauma-focused CBT (which clearly might have muddied the comparison), then CT-PTSD did show a significant advantage (p = 0.047).
Importantly, at the 11-month follow-up, CT-PTSD was significantly better than TAU on the CRIES-8 measure (p = 0.003) showing better long-term benefit.
A mixed-effects model across all time points confirmed a significant overall treatment effect (p = 0.007). Both groups achieved large within-group improvements that were maintained over time.
Secondary outcomes
The study also found that CT-PTSD helped more with difficulties such as anxiety, depression, emotional regulation, irritability, especially at 11-month follow-up (p = 0.003) and parents reported that their young person’s emotional difficulties improved more in the CT-PTSD group.
Drop-out rates were low and there were no major adverse events reported (i.e., no big harms from the therapy) even though many in the study had very complex problems.
Clinical improvement
Overall, CT-PTSD was safe, feasible, and produced sustained clinical benefits across key psychological domains, outperforming TAU and maintaining improvements in PTSD, anxiety, and emotional functioning up to 11 months post-randomisation.
CT-PTSD showed stronger and more sustained improvements than usual care, particularly by the 11-month follow-up.
Conclusions
The DECRYPT trial demonstrated that CT-PTSD (cognitive therapy for PTSD) is a feasible and effective treatment for children and adolescents exposed to multiple traumatic stressors. While the primary post-treatment outcome did not reach statistical significance when compared to a TAU group that could include an active CBT intervention, CT-PTSD showed clear and sustained benefits at 11-month follow-up across self-reported PTSD symptoms, anxiety, depression, and emotional regulation measures.
These findings indicate that structured cognitive therapy can produce meaningful, lasting improvements in complex trauma cases, supporting its implementation within routine CAMHS. Further research should explore strategies to enhance early treatment response and long-term maintenance of gains.
Findings indicate CT-PTSD is a feasible, safe and effective treatment for complex childhood trauma, with benefits across PTSD, anxiety, depression and emotional regulation symptoms that consolidate over time.
Strengths and limitations
The findings in this study are highly relevant for real-world situations because the participants had multiple traumas, comorbid mental health difficulties, and were recruited from standard mental health services within the UK. This means the findings can be argued to apply well to real life clinical scenarios in which most clinicians will work.
Interestingly, the follow-up at 11 months gives information about longer-term effects rather than only immediate results.
When the study excluded TAU participants who had received trauma-focused CBT, the post-treatment difference became statistically significant, likely suggesting that much of the gains in the TAU arm were from receiving an active trauma therapy that reduced the short-term difference.
Commonly, psychotherapy effects grow after the active treatment period as people consolidate learning, apply skills in real life, and improve secondary problems (anxiety, emotion regulation) that secondarily reduce PTSD symptoms. The DECRYPT paper reports larger and more consistent improvements on several secondary measures at 11 months, which fits that pattern.
Another strength from the study was in relation to there being a low drop-out rate, which of course is good because it could mean the therapy was acceptable to many. Further, this also indicates that findings are based on a representative sample, reducing risk of bias. This in turn would strengthen the overall study’s validity and confidence that the results are generalisable and reflect the true effects of the CT-PTSD.
Although the trial was adequately powered for its primary outcome, the sample size remained modest, which may have limited the ability to detect smaller but clinically meaningful differences between CT-PTSD and TAU.
Secondly, the pragmatic design meant that TAU varied considerably across sites, introducing heterogeneity that may have diluted between-group contrasts.
Third, the trial was not blinded; both participants and therapists were aware of treatment allocation, which could have influenced self-reported outcomes through expectancy effects.
Fourth, while follow-up to 11 months provided valuable insight into sustained effects, longer-term outcomes beyond one year remain unknown.
Additionally, the sample predominantly consisted of females and individuals already engaged in mental health services, potentially limiting generalisability to broader or more diverse populations.
The study noted that delays between randomisation and actual therapy start meant that “post-treatment” assessments were not perfectly aligned with the same point in the treatment process for every participant. That could have blurred short-term effects but still allow clearer differences to appear by a later fixed follow-up (11 months).
Despite these limitations, the trial’s pragmatic approach, high retention rates, and strong adherence to treatment protocols enhance confidence in the findings and support the feasibility of delivering CT-PTSD within routine clinical care.
While this feasibility study had many strengths, some differences between groups of participants were not explored.
Implications
Children with multiple adversities are often viewed as “too complex” for standard PTSD treatment protocols, yet the DECRYPT trial demonstrates that structured, trauma-focused CT-PTSD can be both feasible and effective for this population. Although progress may unfold more slowly, the findings powerfully affirm that complexity does not equate to hopelessness. As clinical psychologists working within CAMHS, we were struck by the reminder that healing takes time, and that outcomes might be strongest when clinicians maintain faith in a child’s ability to recover, even when change is gradual and non-linear.
The trial also emphasises the importance of expectation management. Both clinicians and families often hope for rapid symptom reduction, but DECRYPT reminds us that meaningful improvement can be subtle at first, building over time and often continuing beyond the formal therapy period. This perspective can be generalised across all areas of CAMHS, reinforcing that early sessions may not show dramatic progress, yet consistent, steady gains can signal profound and enduring change. Services might therefore consider planning structured follow-up reviews months after discharge to support consolidation of gains, promote resilience, and reduce the likelihood of relapse, though such practices are currently limited by competing demands and service capacity constraints.
Notably, DECRYPT was a pragmatic trial, meaning therapy was delivered under real-world CAMHS conditions with diverse caseloads, service pressures, and mixed presentations. Its success underscores that CT-PTSD can and should be embedded within core CAMHS provision, rather than reserved for only specialist or tertiary trauma services. To do this effectively, clinicians require appropriate training, supervision, and time allocation, particularly when working with children whose difficulties are multifaceted (e.g., trauma combined with self-harm, emotional dysregulation, or family conflict).
The study also brings to light the emotional toll of trauma work on clinicians. Exposure to children’s traumatic narratives can evoke vicarious trauma, compassion fatigue, and burnout. This underlines the need for systems-level support: reflective supervision, manageable caseloads, and ongoing professional development are essential to sustain wellbeing and therapeutic effectiveness. Delivering CT-PTSD effectively therefore depends not only on clinician skill but also on organisational culture, leadership, and flexibility around session structure and length.
In summary, DECRYPT reinforces that trauma-focused CBT should be considered a core, evidence-based intervention within CAMHS. To deliver it well, services must invest in clinician training, reflective spaces, and sustainable infrastructure. Building trauma-informed systems that recognise both the resilience of children and the emotional demands on staff will ensure that complex trauma is met not with avoidance or pessimism, but with structure, compassion, and enduring belief in recovery.
CT-PTSD can be integrated into routine CAMHS, but effective delivery requires adequate training, supervision, and service support.
Statement of interests
No conflicts of interest to disclose.
Edited by
Dafni Katsampa.
Links
Primary paper
Meiser-Stedman R, Allen L, Ashford PA, Beeson E, Byford S, Danese A, Farr A, Finn J, Goodall B, Grainger L, Hammond M, Harmston R, Humphrey A, King D, Lofthouse K, Mahoney-Davies G, Miles S, Moore J, Morant N, Robertson S, Shepstone L, Sims E, Stallard P, Swanepoel A, Trickey D, Trigg K, Vishwakarma R, Wilson J, Dalgleish T, Smith P. (2025)Â A pragmatic randomized controlled trial of cognitive therapy for post-traumatic stress disorder in children and adolescents exposed to multiple traumatic stressors: the DECRYPT trial. World Psychiatry. 2025 Oct;24(3):422-434. doi: 10.1002/wps.21355.
Other references
Ascienzo, S., Sprang, G., & Royse, D. (2021). Gender differences in the PTSD symptoms of polytraumatized youth during isolated phases of trauma-focused cognitive behavioral therapy. Psychological Trauma Theory Research Practice and Policy, 14(3), 488–496.
Lewis SJ, Arseneault L, Caspi A et al. The epidemiology of trauma and post-traumatic stress disorder in a representative cohort of young people in England and Wales. Lancet Psychiatry 2019;6:247-56. 2.
Maercker, A., Cloitre, M., Bachem, R., Schlumpf, Y. R., Khoury, B., Hitchcock, C., & Bohus, M. (2022). Complex post-traumatic stress disorder. The Lancet, 400(10345), 60-72.
Morina, N., Koerssen, R., & Pollet, T. V. (2016). Interventions for children and adolescents with posttraumatic stress disorder: A meta-analysis of comparative outcome studies. Clinical psychology review, 47, 41-54.
Neelakantan, L., Hetrick, S., & Michelson, D. (2019). Users’ experiences of trauma-focused cognitive behavioural therapy for children and adolescents: A systematic review and metasynthesis of qualitative research. European child & adolescent psychiatry, 28(7), 877-897.
National Institute for Health and Care Excellence. Guideline 116: Post-traumatic stress disorder. London: National Institute for Health and Care Excellence, 2018
