Summary: A major new UK trial shows that people living with both psychosis and post-traumatic stress disorder (PTSD) can safely and effectively recover when offered an integrated, trauma-focused therapy. The STAR (Study of Trauma And Recovery) trial is the largest multi-site randomized controlled study to date assessing trauma-focused treatment adapted for people with psychosis.
Across five NHS sites, researchers evaluated 305 participants over five years, addressing a long-standing clinical assumption that directly treating traumatic memories might worsen active psychotic symptoms. The trial’s findings directly challenge that assumption.
Key Facts
- Treatment response: After a 9-month course of integrated Trauma-Focused CBT for psychosis (TF-CBTp), half of those receiving the therapy no longer met clinical criteria for PTSD, compared with just over 20% receiving standard care.
- Changing clinical practice: Historically, people with psychosis were excluded from PTSD trials because of concerns that trauma processing could destabilize psychosis. STAR provides robust evidence that trauma-focused work can be delivered safely for this group.
- High engagement: The trial recorded a low disengagement rate (6.5%), indicating that the tailored, flexible therapy was acceptable and feasible for a highly traumatized population.
- Broad improvements: Participants showed clinically meaningful gains across 22 of 27 measured outcomes, including reductions in PTSD severity, depression, anxiety, suicidal ideation, paranoia, and multisensory hallucinations.
- Scaling the approach: The PICuP Clinic at South London and Maudsley (SLaM) is scaling the intervention and using trial participants with lived experience to help train clinicians and reduce stigma.
Source: King’s College London
Overview
Researchers from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London, in partnership with South London and Maudsley NHS Foundation Trust, led the STAR trial to test whether a trauma-focused therapy integrated with cognitive behavioural therapy for psychosis (CBTp) benefits people with co-occurring PTSD and psychosis. The trial received funding from the UK National Institute for Health and Care Research (NIHR).
PTSD commonly involves intrusive memories (such as flashbacks), heightened arousal, negative beliefs, and avoidance. People with psychosis experience PTSD at much higher rates than the general population—estimates suggest up to five times greater prevalence—and traumatic memories often intertwine with psychotic experiences, shaping delusions and hallucinations.
Historically, clinicians rarely offered trauma-focused therapies to people with psychosis due to concerns about destabilization. The STAR trial instead tested a nine-month, flexible, individualized Trauma-Focused CBTp that directly addresses traumatic memories while also targeting psychosis symptoms and engagement barriers.
Results showed that 50% of participants receiving the integrated therapy no longer met PTSD diagnostic criteria after treatment, compared with about 22% in the treatment-as-usual group. Complex PTSD showed a similar pattern of improvement. The dropout rate was exceptionally low, with only 6.5% disengaging from therapy.
Professor Emmanuelle Peters, Professor of Clinical Psychology at King’s and lead author, said the trial demonstrates that trauma-focused interventions can be delivered safely and effectively to people with psychosis when clinicians directly work with trauma memories, emphasize early engagement, and adapt treatment flexibly to each person’s needs.
Overall, 22 of 27 assessed outcomes showed significant improvement. The primary outcome—PTSD symptom severity measured by CAPS-5—showed a moderate-to-large treatment effect. Additional benefits were observed across psychosis symptoms (including reductions in paranoia and multisensory hallucinations), mood symptoms (depression, anxiety, suicidal ideation), and measures of psychological recovery.
Dr Amy Hardy, Reader in Clinical Psychology at King’s and joint therapy lead, emphasised that denying trauma-focused therapies to people with psychosis has contributed to unequal care. The STAR results indicate these services should be made available to this underserved group.
The PICuP Clinic at SLaM now provides Trauma-Focused CBTp and training to clinicians, led by the STAR therapy team and involving people with lived experience who received the intervention during the trial. One former participant, Shane, now works as a peer-support worker and describes the therapy as restoring trust, confidence, and a sense of control—helping him make sense of long-held experiences and believe recovery is possible.
Dr Nadine Keen, joint therapy lead, commented that the STAR trial should catalyze change in services and commissioning so that trauma-focused CBTp becomes routinely accessible, rather than excluded, for people with psychosis.
Funding: This study was funded by the UK National Institute for Health and Care Research (Health Technology Assessment). The trial involved more than 120 staff across five UK sites (London, Manchester, Newcastle, Oxford, and Sussex) and took five years to complete.
Key Questions Answered:
A: Clinicians feared that directly confronting traumatic memories would destabilize people with psychosis, worsening symptoms such as hallucinations and delusions. As a result, many clinical trials excluded this population and limited their access to evidence-based trauma care.
A: PTSD occurs far more often in people with psychosis than in the general population. In these cases, intrusive trauma memories, hyperarousal, and negative beliefs frequently intersect with psychotic experiences. Traumatic events can shape the content of delusions and hallucinations, making integrated treatment approaches important.
A: The STAR intervention combined trauma-focused techniques with CBTp into a unified, nine-month program. Therapists worked directly with trauma memories, used a flexible, formulation-based approach tailored to each person, and prioritised early engagement and trust-building—factors that likely contributed to the low dropout rate and strong outcomes.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was added by editorial staff.
About this PTSD and psychosis research news
Author: Franca Davenport
Source: King’s College London
Contact: Franca Davenport – King’s College London
Image: The image is credited to Neuroscience News
Original Research: Open access. “Trauma-focused therapy integrated with cognitive behavioural therapy for psychosis for people with post-traumatic stress disorder and psychosis (the STAR trial): a multicentre, pragmatic, randomised trial in the UK” by Peters, E., Swan, S., Underwood, R., Jafari, H., Varese, F., Steel, C., Dudley, R., Greenwood, K., Emsley, R., Keen, N., Bowe, S., Hardy, A., Morrison, A., and the STAR group. Lancet Psychiatry. DOI: 10.1016/S2215-0366(26)00090-8
Abstract
Trauma-focused therapy integrated with cognitive behavioural therapy for psychosis for people with post-traumatic stress disorder and psychosis (the STAR trial): a multicentre, pragmatic, randomised trial in the UK
Background
People with psychosis experience high rates of PTSD, which worsens prognosis and functioning. The STAR trial aimed to evaluate whether a trauma-focused therapy integrated with CBT for psychosis (CBTp) could reduce PTSD symptoms and improve broader clinical outcomes in this population.
Methods
STAR was a rater-blind, parallel-group, pragmatic randomized controlled trial conducted across five UK sites. Adults receiving secondary care who had co-occurring PTSD and psychosis were randomly assigned (1:1) to receive nine months of trauma-focused CBTp plus treatment as usual, or treatment as usual alone. The intervention was a flexible, formulation-driven, individual therapy combining trauma-focused techniques with CBTp principles.
The primary outcome was clinician-rated PTSD symptom severity (CAPS-5) at 4 months (mid-therapy) and 9 months (primary endpoint). Secondary outcomes included PTSD remission rates and clinically significant change, individual symptom clusters, post-traumatic cognitions, dissociation, psychosis symptoms, mood disorders, psychological recovery, and social functioning. Analyses used linear mixed models under an intention-to-treat framework, incorporating data from both time points. Lived experience experts contributed throughout the study. The trial was prospectively registered (ISRCTN93382525).
Findings
Between Oct 1, 2020, and March 20, 2023, 305 participants were randomised (154 to trauma-focused CBTp plus treatment as usual; 151 to treatment as usual). Mean age was 38.9 years (SD 12.4); 42% were men, 56% women, and 2% non-binary or preferred not to say. Most participants (76%) were White. All reported repeated and multiple traumatic events.
Engagement was high: 94% of those allocated to therapy engaged with treatment and 95% received a minimum therapeutic dose. Overall follow-up attendance was 88% at one or both assessment points; 79% provided primary outcome data at 9 months. The trauma-focused CBTp group showed a significant reduction in CAPS-5 scores (adjusted mean difference –8.67; 95% CI –13.41 to –3.94; p=0.0003; Cohen’s d −0.73). Significant benefits were seen on 22 of 27 secondary outcomes (unadjusted for multiple testing), with effect sizes ranging from small to large (Cohen’s d −0.26 to −0.82) for measures including delusions, paranoia, multisensory hallucinations, suicidal ideation, depression, anxiety, stress, and psychological recovery.
There were no meaningful effects on auditory voices, referential beliefs, substance use, or social functioning (Cohen’s d −0.05 to −0.28). PTSD remission occurred in 62 of 125 therapy participants (50%) versus 25 of 116 (22%) in the treatment-as-usual group (odds ratio for PTSD presence 0.11, 95% CI 0.03–0.32; p=0.0001). Clinically significant change on CAPS-5 was observed in 56 (45%) of the therapy group versus 31 (27%) of the control group (OR 4.45, 95% CI 1.59–12.44; p=0.0044). The number needed to treat for PTSD remission was 4. No unexpected serious adverse events related to trial procedures were reported; the most common adverse events in both groups were physical illness or injury.
Interpretation
Trauma-focused CBTp is safe, acceptable, and effective for people with co-occurring psychosis and PTSD. The findings support offering trauma-focused psychological interventions to this underserved population rather than excluding them from such care.
Funding
UK National Institute for Health and Care Research (Health Technology Assessment).