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

<jats:title>Abstract</jats:title>
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<jats:title>Objective</jats:title>
<jats:p>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).</jats:p>
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<jats:title>Data sources</jats:title>
<jats:p>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.</jats:p>
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<jats:title>Study selection</jats:title>
<jats:p>Meta-analyses addressing metacognitive interventions targeting psychotic symptoms were eligible for meta-review.</jats:p>
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<jats:title>Data extraction and synthesis</jats:title>
<jats:p>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.</jats:p>
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<jats:title>Main outcomes and measures</jats:title>
<jats:p>Main outcomes were levels/severity of positive symptoms, delusions and hallucinations, negative symptoms, and overall psychotic symptoms after intervention.</jats:p>
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<jats:title>Results</jats:title>
<jats:p>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%; <jats:italic>N</jats:italic> = 35, <jats:italic>g</jats:italic> = 0.473 [0.295, 0.651], <jats:italic>I</jats:italic>
<jats:sup>
<jats:italic>2</jats:italic>
</jats:sup> = 74.64), delusions (60%; <jats:italic>N</jats:italic> = 24, <jats:italic>g</jats:italic> = 0.639 [0.389, 0.889], <jats:italic>I</jats:italic>
<jats:sup>
<jats:italic>2</jats:italic>
</jats:sup> = 80.01), hallucinations (100%; <jats:italic>N</jats:italic> = 9, <jats:italic>g</jats:italic> = 0.265 [0.098, 0.432], <jats:italic>I</jats:italic>
<jats:sup>
<jats:italic>2</jats:italic>
</jats:sup> = 6.1), negative symptoms (100%; <jats:italic>N</jats:italic> = 17, <jats:italic>g</jats:italic> = 0.233 [0.1, 0.366], <jats:italic>I</jats:italic>
<jats:sup>
<jats:italic>2</jats:italic>
</jats:sup> = 34.78), and overall symptoms (50%; <jats:italic>N</jats:italic> = 37, <jats:italic>g</jats:italic> = 0.392 [0.245, 0.538], <jats:italic>I</jats:italic>
<jats:sup>
<jats:italic>2</jats:italic>
</jats:sup> = 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 <jats:italic>metaumbrella.org</jats:italic> 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.</jats:p>
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<jats:title>Conclusions and relevance</jats:title>
<jats:p>There is consistent evidence that MCT ameliorates positive symptoms and delusions in schizophrenia.</jats:p>
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