The benefits of yoga as an intervention for depression: a meta–analysis

Depression is a major societal issue that affects a large proportion of the population. Yoga has been introduced as a viable alternative approach to reduce symptoms. While prior studies have used meta–analysis to examine the benefits of yoga for depression, these studies incorporated a small number of studies and were limited in their ability to conduct a sub–group analysis. The purpose of this study was to quantify the effect size of yoga in the treatment of depression. Inclusion criteria included experimental, quasi–experimental, and feasibility studies that examined yoga with physical postures (asanas) as a treatment for depression. Nine moderator variables were examined including type of yoga, components of yoga (i.e., breathing, meditation, or relaxation), experience of yoga instructor, depression diagnosis, type of comparison group, research design, and length of treatment. Risk of bias was assessed using the Jadad instrument. Electronic databases were used to identify studies, and the search concluded on January 31st, 2022. A total of 152 studies (150 articles) met the inclusion criteria in this meta–analysis with 8210 participants assessed. The overall weighted effect size of yoga for treatment of depression was Hedges’ g = 0.55 (95% CI 0.44–0.65), demonstrating a medium effect. Meta–regression and subgroup analyses found larger effect sizes as the amount of yoga practiced increased, when relaxation was practiced, and when participants had been clinically diagnosed with depression. Funnel plot and trim–and–fill procedure found little evidence of publication bias and the fail–safe number was 21783. These results demonstrate that yoga is an effective integrative approach in the treatment of depression. This study was limited by the methodological quality of the individual studies that make up the larger analysis, including participants who were not blind to the procedure and a failure to report withdrawals and dropouts.