Highlights
- The STAR trial, a large multicentre UK randomized controlled trial, validates trauma-focused CBTp as efficacious for adults with co-occurring PTSD and psychosis.
- Trauma-focused CBTp significantly reduces PTSD symptom severity, with half of therapy recipients achieving PTSD remission by 9 months.
- Secondary benefits include improvements in paranoia, delusions, hallucinations (non-voice modalities), mood symptoms, suicidal ideation, and psychological recovery.
- Trauma-focused CBTp is safe and highly acceptable, with symptom exacerbation not linked to drop-out or poorer outcomes.
Background
Psychosis affects approximately 1% of the population and is frequently complicated by post-traumatic stress disorder (PTSD), with prevalence estimates markedly higher than the general population. PTSD in individuals with psychosis contributes to worse prognosis, more severe symptoms, and heightened distress. Historically, concerns about exacerbating psychotic symptoms have limited provision of trauma-focused therapies in this group, resulting in an underserved patient population lacking evidence-based psychological treatments tailored to their complex clinical profile.
Cognitive Behavioural Therapy for psychosis (CBTp) is a first-line psychological intervention targeting psychotic symptoms but traditionally has not integrated trauma-focused components. Trauma-focused therapies (e.g., prolonged exposure, EMDR) are evidence-based for PTSD but have been underutilized in psychosis due to safety concerns. This context necessitates rigorous trials evaluating integrated trauma-focused interventions adapted for psychosis to improve outcomes and address trauma sequelae in this population.
Key Content
STAR Trial: Design, Intervention, and Outcomes
The STAR trial (Peters et al., 2026) was a pragmatic, rater-blind, parallel-group randomized controlled trial conducted across five UK secondary care sites, enrolling 305 adults with documented co-occurring PTSD and psychosis. Participants were randomized 1:1 to receive trauma-focused CBTp plus treatment as usual (TAU) or TAU alone. The intervention was a flexible, individualized formulation-based therapy lasting 9 months, integrating trauma-focused therapeutic elements within the CBTp framework.
The primary endpoint was PTSD severity measured by the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) at 9 months, with an intermediate assessment at 4 months. Secondary outcomes included PTSD remission rates, symptom clusters, psychosis symptoms (delusions, hallucinations), mood disorders, psychological recovery, and social functioning.
Primary and Secondary Outcomes
The trial demonstrated a statistically significant and clinically meaningful reduction in PTSD symptom severity at 9 months (adjusted mean difference -8.67 on CAPS-5; p=0.0003; Cohen’s d -0.73). PTSD remission occurred in 50% of therapy participants versus 22% in TAU, with an odds ratio of 0.11 favoring trauma-focused CBTp. Clinically significant CAPS-5 improvements were also higher in the therapy group (45% vs. 27%). The number needed to treat for PTSD remission was 4, highlighting the intervention’s efficiency.
Notably, trauma-focused CBTp also improved multiple psychosis symptoms, including delusions, paranoia, and hallucinations in modalities other than voices. Mood symptoms (depression, anxiety, stress), suicidal ideation, and measures of psychological recovery improved significantly. There were, however, no significant effects on auditory hallucinations (voices), referential beliefs, substance use, or social functioning.
Safety and Acceptability
Engagement was high, with 94% of therapy participants attending and 95% receiving a minimal therapeutic dose. Adverse events (physical illness/injury) were balanced across groups, with no treatment-related serious adverse events reported. The study underlined that symptom exacerbations during trauma-focused therapy, as observed in related studies (e.g., van den Berg et al., 2023), are common but not linked to treatment drop-out or poorer clinical outcomes, supporting safety in this high-risk group.
Complementary Evidence and Methodological Advances
Supporting studies include recent RCTs and investigations into trauma-focused therapies for psychosis:
– The EMDRp feasibility trial (Steel et al., 2024) in early psychosis populations demonstrated promising efficacy signals for trauma-focused EMDR integrated within standard care for PTSD and psychosis symptoms, with robust treatment adherence and retention.
– Experience sampling studies (Smeets et al., 2025) report modest reductions in distressing voice-hearing post-trauma-focused therapy, suggesting potential indirect benefits on auditory hallucinations, although the STAR trial did not find significant effects on voices.
– Novel imagery rescripting protocols (Morrison et al., 2022) targeting intrusive trauma memories in psychosis show feasibility, safety, and symptomatic improvement, indicating that refining trauma-targeted techniques may enhance psychosis care.
– Critical exploration of symptom exacerbation profiles across trauma therapies (van den Berg et al., 2023) informs clinicians and patients about the natural fluctuations in PTSD symptoms during treatment, reinforcing the importance of persistence and symptom management strategies.
The STAR trial exemplifies methodological rigor through large sample size, multicentre recruitment enhancing generalizability, stratified randomization, intention-to-treat analysis incorporating multiple time points, and inclusion of lived experience experts, ensuring patient-centeredness and ecological validity.
Expert Commentary
The STAR trial marks a pivotal advance in bridging the treatment gap for individuals with psychosis and comorbid PTSD. By integrating trauma-focused elements within CBTp, it confirms that psychological interventions can be adapted safely and effectively for this underserved population. The sizable effect on PTSD symptoms and broad improvements in psychotic and mood symptoms underscore trauma’s central pathogenic role in this subgroup.
The study challenges previous clinical hesitancy about trauma-focused therapy in psychosis, providing high-quality evidence mitigating safety concerns. Clinicians should reconsider exclusion of trauma interventions solely based on psychosis diagnosis. Importantly, while voices did not improve significantly, the reduction in other psychotic experiences and mood symptoms may contribute to overall functional gains and quality of life.
Limitations include the absence of effects on social functioning and auditory hallucinations, highlighting areas for future research. Further mechanistic studies are required to elucidate biological and cognitive pathways whereby trauma-focused CBTp exerts benefits and to optimize components targeting auditory hallucinations.
Moreover, the inclusion of trauma-focused therapies such as EMDR and imagery rescripting in early psychosis stages and chronic populations warrants expansion, alongside exploration of digitally delivered or stepped-care models to enhance accessibility.
Guidelines should now incorporate trauma-focused CBTp as standard care for PTSD in psychosis. Multidisciplinary teams must be equipped with training and supervision to deliver these interventions, and policy makers should ensure funding and integration within mental health services.
Conclusion
The STAR trial confirms that trauma-focused therapy integrated with CBTp is a safe, acceptable, and efficacious intervention for adults with co-occurring PTSD and psychosis, substantially reducing PTSD symptoms and improving psychosis-related outcomes. Its findings empower mental health services to provide evidence-based, trauma-informed care to a vulnerable and historically neglected patient population.
Future research must evaluate longer-term outcomes, refine treatment targeting for refractory symptoms such as voices, and expand this approach across diverse clinical settings. Overall, the integration of trauma-focused therapy into psychosis care represents a critical paradigm shift towards holistic, personalized mental health treatment.
References
- 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, STAR group. 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. 2026 Jul;13(7):549-566. PMID: 42309103.
- Steel C, Tran M, Hardy A, et al. Trauma-focused therapy in early psychosis: results of a feasibility randomized controlled trial of EMDR for psychosis (EMDRp) in early intervention settings. Psychol Med. 2024 Apr;54(5):874-885. PMID: 37882058.
- Smeets L, Daalman K, et al. The effect of trauma-focused therapy on voice-hearing: An experience sampling study. Psychol Psychother. 2025 Mar;98(1):25-39. PMID: 39494655.
- van den Berg D, de Bont PAJ, van der Vleugel BM, et al. The bumpy road of trauma-focused treatment: Posttraumatic stress disorder symptom exacerbation in people with psychosis. J Trauma Stress. 2023 Apr;36(2):299-309. PMID: 36719408.
- Morrison AP, Hardy A, et al. A randomised multiple baseline case series of a novel imagery rescripting protocol for intrusive trauma memories in people with psychosis. J Behav Ther Exp Psychiatry. 2022 Jun;75:101699. PMID: 34813973.
