Substance Use Within Trials of Psychological Interventions for Psychosis: Sample Inclusion, Secondary Measures, and Intervention Effectiveness.

Introduction: Current clinical guidelines recommend that patients with co-occurring psychosis and alcohol or substance use disorders (A/SUD) receive evidenced-based treatment for both disorders, including psychological intervention for psychosis. However, the efficacy of such treatments for individuals with co-occurring psychosis and A/SUD is unclear.

Study design: Randomized controlled trials (RCTs) of psychological interventions for psychosis were systematically reviewed, to investigate how alcohol and substance use has been accounted for across sample inclusion and secondary measures. Findings from trials including individuals with co-occurring alcohol or substance use issues were then narratively summarized using the Synthesis Without Meta-Analysis guidelines, to indicate the overall efficacy of psychological interventions for psychosis, for this comorbid population.

Study results: Across the 131 trials identified, 60.3% of trials excluded individuals with alcohol or substance use issues. Additionally, only 6.1% measured alcohol or substance use at baseline, while only 2.3% measured alcohol or substance use as a secondary outcome. Across trials explicitly including individuals with alcohol or substance use issues, insufficient evidence was available to conclude the efficacy of any individual psychological intervention. However, preliminary findings suggest that psychoeducation (PE) and metacognitive therapy (MCT) may be proposed for further investigation.

Conclusion: Overall, co-occurring alcohol and substance use issues have been largely neglected across the recent RCTs of psychological interventions for psychosis; highlighting the challenges of making treatment decisions for these individuals using the current evidence base.