New research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London and published in The Lancet Psychiatry has found that people with psychosis experiencing Post Traumatic Stress Disorder (PTSD) can benefit from a Trauma-Focused therapy integrated with Cognitive Behaviour Therapy for psychosis (CBTp).
The STAR (Study of Trauma And Recovery) study , funded by the National Institute for Health and Care Research (NIHR) led by researchers at King's IoPPN and South London and Maudsley NHS Foundation Trust (SLaM), recruited 305 participants and is the largest multi-site randomised controlled trial to date of a trauma-focused therapy for people with co-occurring diagnoses of psychosis and PTSD.
PTSD is characterised by intrusive trauma memories such as 'flashbacks' and other types of re-experiencing, negative appraisals, hyperarousal, and avoidance of trauma reminders. The prevalence of PTSD in people with psychosis is up to five times that in the general population, with PTSD symptoms often intertwined with psychosis symptoms such as delusions and hallucinations, and traumatic events often shaping their content.
In the past people with psychosis have been excluded from almost all PTSD research trials, and clinicians were wary of delivering Trauma-Focused therapy in routine clinics for fear of making the psychosis symptoms worse. But this study showed that an integrated Trauma-Focused-CBTp, lasting 9-months, was safe and highly effective with this group. Half of the participants who received the therapy no longer met PTSD criteria post-therapy, compared to just over 20 per cent receiving treatment as usual, despite all participants reporting repeated and multiple traumas. A similar pattern was found for complex PTSD.
There were exceptionally low rates of disengagement from therapy (6.5 per cent), demonstrating the therapy is highly acceptable.
Professor Emmanuelle Peters, Professor of Clinical Psychology at King's and the study's first author said: "It is now clear that trauma-focused therapies can be delivered safely and effectively for people with PTSD and psychosis. Our results are robust in demonstrating that this intervention, which includes working on the trauma memory directly, a focus on engagement, and a flexible approach tailored to the individual, is safe, highly acceptable and effective on a range of PTSD, psychosis, and emotional well-being outcomes."
Overall participants showed significant improvements in 22 out of 27 assessed outcomes. The primary outcome, PTSD symptom severity, demonstrated a moderate-to-large effect size, with additional effects ranging from large to small across psychosis symptoms (paranoia and multisensory hallucinations), mood disorders (depression, anxiety and suicidal ideation), and psychological recovery.
Dr Amy Hardy, Reader in Clinical Psychology at King's and the joint-last author and joint-Therapy Lead for the study, said: "The results challenge a longstanding gap in mental healthcare, where people with psychosis have been excluded from trauma-focused therapies. Our findings demonstrate that this must change, to ensure those historically denied access can receive evidence-based care."
Professor Peters leads a specialist psychological therapies team for outpatients with psychosis, the PICuP Clinic , based at SLaM. PICuP now provides Trauma-focused CBTp and training in the intervention to clinicians working with individuals with psychosis, led by the STAR Therapy Leads Dr Nadine Keen (PICuP Coordinator) and Dr Amy Hardy (PICuP and SLaM Psychology & Psychotherapy Trauma Informed Care for Psychosis Lead), alongside people with lived experience of trauma and psychosis who received the therapy in the trial.
One such participant, Shane now works as a Peer-Support Worker in PICuP and with Professor Peters on the Let's Talk research trial at King's and South London and Maudsley, delivering a peer-led programme to address internalised stigma for people with psychosis. He said: "STAR therapy gave me the tools to make sense of experiences I had carried for years and change how I see myself and others. I didn't just learn ways to manage and reshape trauma memories - I rebuilt trust, confidence, and a sense of connection. It gave me back a feeling of control and the belief that recovery is possible."
Dr Nadine Keen, STAR joint-Therapy Lead, commented that "We hope the STAR trial will be a gamechanger for the psychological treatment of this highly complex and marginalised population, motivating commissioners and services to prioritise implementation of Trauma-Focused CBTp. This therapy can transform lives and underscores an ethical imperative: clinical services and research should not inadvertently perpetuate trauma survivors' silence through exclusion."
This research was possible thanks to funding by the National Institute for Health and Care Research (Health Technology Assessment). Over 120 people in five UK sites (London; Manchester; Newcastle; Oxford and Sussex) were involved in delivering the trial, which took five years to complete.
'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 et al (2026) was published in The Lancet Psychiatry DOI 10.1016/S2215-0366(26)00090-8
