Metacognitive training for psychosis (MCT): a systematic meta-review of its effectiveness

Metacognitive training for psychosis (MCT) targets cognitive biases implicated in the pathogenesis of psychosis, e.g., jumping to conclusions, overconfidence in errors, and inflexibility. This systematic meta-review investigated the current meta-analytic evidence for the effectiveness of MCT with respect to core symptom features in schizophrenia (i.e., positive symptoms, delusions and hallucinations, negative symptoms, and overall psychotic symptoms).

This meta-review was registered with PROSPERO (CRD42023447442) on July 28, 2023. Articles were searched across five electronic databases from January 1, 2007 to September 1, 2023.

Meta-analyses addressing metacognitive interventions targeting psychotic symptoms were eligible for meta-review.

PRISMA guidelines were followed when applicable. Data extraction was done independently by two authors (AM, AS). A random-effects model was used to pool data within meta-analyses.

Main outcomes were levels/severity of positive symptoms, delusions and hallucinations, negative symptoms, and overall psychotic symptoms after intervention.

Eight meta-analyses and two re-analyses were included for meta-review. A total of eight analyses provided sufficient data for analysis. Significant evidence was found in favor of MCT for positive symptoms (85.71%; N = 35, g = 0.473 [0.295, 0.651], I² = 74.64), delusions (60%; N = 24, g = 0.639 [0.389, 0.889], I² = 80.01), hallucinations (100%; N = 9, g = 0.265 [0.098, 0.432], I² = 6.1), negative symptoms (100%; N = 17, g = 0.233 [0.1, 0.366], I² = 34.78), and overall symptoms (50%; N = 37, g = 0.392 [0.245, 0.538], I² = 65.73). None of the meta-analyses included a large enough sample size to meet the criteria for 'suggestive', 'convincing', or 'highly convincing' evidence according to metaumbrella.org guidelines (required sample size > 1000 cases). None of the meta-analyses scored 'moderate' or 'high' on methodological quality. Meta-analyses with significant results were more recent and/or considered more primary studies.

There is consistent evidence that MCT ameliorates positive symptoms and delusions in schizophrenia.