Immediate and Sustained Outcomes and Moderators Associated With Metacognitive Training for Psychosis: A Systematic Review and Meta-analysis

IMPORTANCE: A substantial increase in the number of trials examining metacognitive training (MCT) for psychosis necessitates an updated examination of the outcomes associated with MCT. OBJECTIVES: To review the immediate and sustained associations of MCT with proximal (directly targeted) and distal (indirectly influenced) outcomes and assess treatment- and participant-related moderators to identify the potential factors associated with the expected heterogeneity of effect sizes. DATA SOURCES: Eleven electronic databases were searched from 2007 to June 3, 2021 (alert until September 10, 2021). Reference lists of earlier meta-analyses and included reports were screened. STUDY SELECTION: Reports examined MCT and included participants with schizophrenia spectrum and related psychotic disorders (1045 reports identified; 281 assessed). There were no age, sex, gender, race and ethnicity, language, or study design restrictions. Two reviewers performed the selection of studies to be analyzed. DATA EXTRACTION AND SYNTHESIS: The Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline was followed. Data were extracted by 3 reviewers and pooled using random effects models. Hedges g effect sizes were computed. The Mixed-Methods Appraisal tool was used to assess study quality. MAIN OUTCOMES AND MEASURES: Proximal outcomes were global positive symptoms, delusions, hallucinations, and cognitive biases. Distal outcomes were self-esteem, negative symptoms, quality of life, well-being, and functioning. Immediate and sustained outcomes were examined. Meta-regressions, subgroup, and sensitivity analyses assessed moderators. RESULTS: This systematic review and meta-analysis included 43 studies (46 reports). Forty reports were synthesized in meta-analysis (N=1816 participants) and 6 reports were included in narrative review. In the studies examined, MCT was associated with positive symptoms (g = 0.50; 95% CI, 0.34-0.67), delusions (g = 0.69; 95% CI, 0.45-0.93), hallucinations (g = 0.26; 95% CI, 0.11-0.40), cognitive biases (g = 0.16; 95% CI, 0.03-0.29), self-esteem (g = 0.17; 95% CI, 0.03-0.31), negative symptoms (g = 0.23; 95% CI, 0.10-0.37), and functioning (g = 0.41; 95% CI, 0.12-0.69). These associations were maintained up to 1 year. The quality of life effect size was nonsignificant (g = 0.20; 95% CI, −0.07 to 0.47); only 1 study assessed well-being. Publication year was associated with moderated hallucinations (β = 0.04; 95% CI, 0.00-0.07). Overall, narrative review results corroborated meta-analytic findings. CONCLUSIONS AND RELEVANCE: In this meta-analysis, MCT for psychosis was associated with benefits up to 1 year postintervention in several treatment contexts. These findings suggest that MCT may merit integration in treatment guidelines for schizophrenia.