Efficacy of metacognitive therapy in improving mental health: A meta-analysis of single-case studies

Context. Metacognitive therapy and one of its treatment components, the attention training technique are increasingly being delivered to improve mental health. Objective. To examine the efficacy of metacognitive therapy and/or attention training technique on mental health outcomes from single-case studies. Methods. Fourteen studies (53 patients) were included. The d-statistic for multiple baseline data and the percentage change index were used to compute the effect sizes. Results. Metacognitive therapy has a large effect on depression, anxiety, other psychopathological symptoms, and all outcomes together. Effect sizes were significantly moderated by the number of sessions, the severity and duration of symptoms, and patient gender, but not by study quality or attention training technique when used as a stand-alone treatment. At the follow-up, 77.36% of the individuals were considered recovered or had maintained improvement. Conclusion. Metacognitive therapy and attention training technique strongly contribute to improving mental health outcomes. This study effectively informs evidence-based practice in the clinical milieu.