Summary: A large UK trial demonstrates that people living with both psychosis and post-traumatic stress disorder (PTSD) can safely and effectively recover using an integrated, trauma-focused therapy. The STAR (Study of Trauma And Recovery) trial is the largest multi-site randomized controlled study to date examining trauma-focused treatment for this population.
Across five sites and five years, 305 participants were assessed. The findings challenge the long-held clinical concern that processing traumatic memories in people with active psychosis will worsen hallucinations or delusions. Instead, the trial shows clear benefits from a tailored, trauma-focused approach combined with cognitive behavioural therapy for psychosis (CBTp).
Key Facts
- Treatment effectiveness: After nine months of integrated trauma-focused CBTp (TF‑CBTp), 50% of treated participants no longer met diagnostic criteria for PTSD, compared with just over 20% in the treatment-as-usual group.
- Overturning exclusionary practice: Historically, people with psychosis were excluded from PTSD trials due to clinician concerns about destabilisation. The STAR results provide robust evidence that direct trauma memory work is safe in this group.
- High engagement: The therapy recorded a low disengagement rate of 6.5%, indicating the intervention is acceptable and feasible for a complex, highly traumatized cohort.
- Broad clinical benefits: Participants showed significant improvements in 22 of 27 clinical outcomes measured, including moderate-to-large reductions in PTSD severity and meaningful decreases in depression, anxiety, suicidal ideation, paranoia, and multisensory hallucinations.
- Scale-up and lived-experience involvement: The PICuP Clinic at South London and Maudsley (SLaM) is expanding the approach and involving people with lived experience to co-deliver training and reduce internalized stigma.
Source: King’s College London
New research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London, published in The Lancet Psychiatry, shows that trauma-focused therapy integrated with CBT for psychosis helps people who experience both PTSD and psychosis. Funded by the UK National Institute for Health and Care Research (NIHR) Health Technology Assessment programme, the STAR trial recruited 305 adults across five NHS sites and compared trauma-focused CBTp plus treatment as usual with treatment as usual alone.
PTSD commonly involves intrusive trauma memories (for example, flashbacks), negative interpretations of events, heightened arousal, and avoidance. The prevalence of PTSD among people with psychosis is substantially higher than in the general population—up to five times greater—and PTSD symptoms often overlap or interact with psychotic symptoms, influencing the content of delusions and hallucinations.
Because clinicians have traditionally worried that confronting traumatic memories could destabilize psychosis, people with psychosis were usually excluded from PTSD research. The STAR trial directly addressed this gap by delivering a flexible, individualized nine-month trauma-focused CBTp that includes direct work on trauma memories alongside psychosis-focused cognitive behavioural strategies. The results show that this combined approach is both safe and effective.
Half of those who received the therapy no longer met criteria for PTSD after treatment, compared to just over one in five who received usual care. Similar improvements were observed for complex PTSD. Most participants (94% of those allocated to therapy) engaged with treatment and 95% received at least a minimal therapeutic dose, demonstrating the model’s practicality in routine services.
Professor Emmanuelle Peters, lead author and Professor of Clinical Psychology at King’s, emphasized that the trial demonstrates trauma-focused therapies can be delivered safely to people with co-occurring psychosis and PTSD when the approach is flexible, engagement-focused, and tailored to individual needs. Dr Amy Hardy, joint therapy lead, highlighted that the findings should prompt services and commissioners to ensure people with psychosis are not excluded from evidence-based trauma care.
The PICuP Clinic at SLaM now offers Trauma-Focused CBTp and provides training for clinicians. The clinic’s training includes people with lived experience who participated in the STAR trial and now contribute to service delivery and anti-stigma work. One former participant described how STAR therapy helped him make sense of long-held experiences, rebuild trust and confidence, and regain a sense of control and hope for recovery.
The trial’s findings are notable for the range of improved outcomes: PTSD symptom severity showed a moderate-to-large effect, and benefits were also found across several psychosis-related and mood-related measures. No unexpected trial-related serious adverse events were reported, and the most common adverse events were physical illnesses or injuries unrelated to treatment procedures.
Funding: UK National Institute for Health and Care Research (Health Technology Assessment). The trial involved over 120 clinicians and researchers across five UK sites—London, Manchester, Newcastle, Oxford, and Sussex—and took five years to complete.
Key Questions Answered
A: Clinicians long feared that confronting traumatic memories might destabilize individuals with psychosis and worsen symptoms such as hallucinations and delusions. As a result, this group was frequently excluded from PTSD research and denied access to front-line trauma therapies.
A: PTSD is much more common among people with psychosis than in the general population. In many cases, trauma memories, flashbacks, and hyperarousal become intertwined with psychotic experiences—traumatic events often shape the themes and content of delusions and hallucinations.
A: The STAR therapy combined trauma-focused techniques with CBT for psychosis into a nine-month, formulation-based program. Its flexibility, individualized planning, and strong focus on building engagement and trust led to very low dropout rates and high acceptability, while allowing direct and safe work on trauma memories.
Abstract (Concise)
Background: People with psychosis have high rates of PTSD and poorer clinical outcomes. The trial aimed to evaluate a trauma-focused CBTp approach for this population.
Methods: STAR was a rater-blind, parallel-group randomized controlled trial across five UK sites. Adults with co-occurring PTSD and psychosis were randomized to trauma-focused CBTp plus usual care versus usual care alone. The therapy was a nine-month, individualized, formulation-based intervention integrating trauma-focused components with CBTp. The primary outcome was PTSD symptom severity at nine months, measured with the clinician-administered PTSD Scale for DSM-5 (CAPS‑5).
Findings: Among 305 participants randomized between Oct 2020 and March 2023, those receiving trauma-focused CBTp showed significant reductions in PTSD severity (adjusted mean difference −8.67 on CAPS‑5; Cohen’s d −0.73) and improvements on 22 of 27 secondary outcomes. Fifty percent of therapy participants achieved PTSD remission versus 22% in usual care. No unexpected serious adverse events related to trial procedures occurred.
Interpretation: Trauma-focused CBTp is safe, acceptable, and effective for people with co-occurring psychosis and PTSD. Services should extend access to trauma-focused psychological treatments for this historically underserved group.
Research citation
Peters E., Swan S., Underwood R., Jafari H., Varese F., Steel C., et al. “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.” Lancet Psychiatry. DOI: 10.1016/S2215-0366(26)00090-8.
Notes
- This article summarizes peer-reviewed research and has been edited for clarity and context.
- The trial was conducted with contributions from people with lived experience at every stage, including intervention delivery and training.