Effectiveness of metacognitive interventions for mental disorders in adults: A systematic review protocol (METACOG)

Introduction: Whereas the efficacy of cognitive-behavioural therapy has been demonstrated for a variety of mental disorders, there is still need for improvement, especially regarding less prevalent or more severe disorders. Recently, metacognitive interventions have been developed and are now available for a variety of diagnoses. Still, a systematic review investigating the effectiveness of different metacognitive interventions for various mental disorders is missing. Methods and analysis: Randomised controlled trials (RCTs), cross-over and cluster RCTs and non-randomised controlled trials on metacognitive interventions (ie, metacognitive therapy, metacognitive training, others) in adults with any mental disorder will be included. As comparators, another psychological or pharmacological treatment, a combined psychological and pharmacological treatment, treatment as usual or no active treatment are eligible. Outcomes refer to efficacy and acceptability of metacognitive interventions. Ethics and dissemination: In light of the popularity of metacognitive interventions, the systematic review will provide researchers, clinicians and patients with substantial information on the intervention's effectiveness across different mental disorders. Results will be published in peer-reviewed journals and disseminated through a patient workshop.