A Meta-Analysis of Comparing the Efficacy of the Third Wave of Behavior Therapies on Depression in Iran: Comparing Acceptance and Commitment Therapy, Mindfulness-Based Therapy and Metacognitive Therapy (2001-2017)

Introduction: In recent years, multiple studies have examined the efficacy of the third wave of behavior therapies for depression disorders. This research aimed to compare the results of studies investigating the efficacy of acceptance and commitment therapy, mindfulness-based therapy and metacognitive therapy on depression in Iranian population. Methods: Meta-analysis method was employed in this research and 69 publications which were methodology accepted were selected after a careful study of research studies. Also, the checklist was used to check inclusion criteria and extracted data from each study and finally 70 effect sizes were reported. Results: The results showed that acceptance and commitment therapy, mindfulness-based therapy and metacognitive therapy had been effective for depression at significant level less than 0.05. The size of the combined effect (in terms of scale standardized mean difference) of them were reported 1.565, 1.206 and 1.891 respectively. Also study of type of treatment as a moderating variable showed that metacognitive therapy is more effective in reducing symptoms of depression than mindfulness-based therapy. Conclusions: The results of meta-analysis showed that the third wave of behavior therapies specially metacognitive therapy are effective at reducing symptoms of depression.