The STAR trial, a large multi-site randomized study, shows that integrating trauma-focused therapy with CBT for psychosis (CBTp) over nine months safely reduces PTSD symptoms in people with co-occurring psychosis and PTSD, challenging the belief that trauma work worsens psychosis.

Engagement was strong, with only a 6.5% dropout rate, indicating the approach is acceptable to a heavily traumatized population.

Remission rates were higher in the therapy group, with 62/125 achieving PTSD remission versus 25/116 in the control; clinically meaningful change on CAPS-5 favored the therapy group (56/125 vs 31/116).

The study enrolled 305 adults across five UK sites (London, Manchester, Newcastle, Oxford, Sussex) from 2020–2023, with 154 assigned to trauma-focused CBTp and 151 to treatment as usual; 144 in the therapy arm engaged with treatment and 146 received a minimal therapeutic dose.

No serious adverse events were linked to the trial; the therapy did not worsen psychosis and was safe and well-tolerated.

Approximately half of participants receiving trauma-focused CBTp no longer met PTSD criteria after nine months, compared with just over 20% in treatment as usual, with similar remission patterns for complex PTSD.

Funded by NIHR Health Technology Assessment and published in Lancet Psychiatry, the STAR trial supports making trauma-focused CBTp a standard option for people with psychosis and PTSD, addressing an unmet need in mental health services.

Participants showed broad improvements across 22 of 27 secondary outcomes, including reduced depression, anxiety, suicidal ideation, paranoia, multisensory hallucinations, and better overall psychological recovery.

The intervention was scaled through the PICuP Clinic at SLaM, incorporating lived-experience input to train clinicians and address internalized stigma, with peer-support illustrating positive personal transformation.