The effect of metacognitive therapy on depressive symptoms from a transdiagnostic perspective: a systematic review, meta-regression and meta-analysis

BACKGROUND: Metacognitive therapy (MCT) is a modern therapeutic approach gaining wider use for psychological problems. This review evaluates the efficacy of MCT on depressive symptom severity. METHOD: This review followed Cochrane and PRISMA-2020 guidelines. A comprehensive literature search revealed 51 studies on the efficacy of MCT, of which 33 were trials. A random-effects model was used to assess treatment efficacy. We calculated effect sizes using (Hedge's g) SMD for the percentage change index. (PROSPERO registration (CRD420251024202)). RESULTS: Within-group aggregate effect sizes for the depression outcome measure, mean change for studies was Hedge's g = (-2.29), 95% CI (-2.75 | -1.83), (P < 0.001). Between-group analyses combined effect size for depression outcome, the mean change of aggregate effect size for the studies comparing MCT to the control group was Hedge's g =(-1.28), 95% CI (-1.71 | -0.86). Both effect sizes were highly significant (Ps < 0.000). CONCLUSIONS: Findings indicate that metacognitive therapy appears to be an efficacious intervention for depressive disorders and is superior to waitlist control conditions. However, interpretation is limited by small sample sizes and the lack of active comparison groups. Future investigations should employ larger samples and include head-to-head comparisons with other evidence-based psychotherapies.