Metacognitive Training for Psychosis (MCT): A Systematic Review of the Meta-Analyses Regarding the Effectiveness of Psychotic Symptom Reduction in Schizophrenia

This meta-review aimed at summarizing and providing a detailed, as well as comprehensive overview of the current data and findings regarding the effectiveness of metacognitive training (MCT) in the reduction of schizophrenia symptoms, specifically overall symptoms, positive symptoms [including delusions and hallucinations], and negative symptoms. A total of nine meta- analyses, two re-analyses, and two letters to the author were discussed and analyzed in a systematic review. Study overlap (CCA; Pieper et al., 2014) and methodological quality were assessed (AMSTAR-2; Shea et al., 2017). A classification of the evidence was carried out using metaumbrealla.org (Gosling et al., 2023). None of the meta-analyses were considered to be of high methodological quality or having provided convincing evidence in favor of MCT. However, the most recent meta-analysis (Penney et al., 2022) provided a considerable amount of evidence in favor of MCT, as it is the largest meta-analysis on this topic to date and was ranked highest in methodological quality. Future research should aim at testing the robustness of these findings. Nonetheless, this meta-review is subject to several limitations associated with the strict guidelines of the AMSTAR-2 checklist, as well as the use of metaumbrella.org (Gosling et al., 2023), the statistical analysis tool for meta-reviews. This dissertation was conducted under the supervision of the main developer of MCT, Steffen Moritz.