Effectiveness of traditional meditation retreats: A systematic review and meta-analysis.

Traditional meditation retreats are moderately to largely effective at reducing depression, anxiety, and stress, and improving quality of life, according to a meta-analysis of 21 studies involving 2,912 participants. Effect sizes were moderate in pre-post analyses (Hedge's g = 0.45) and when comparing retreats to control groups (Hedge's g = 0.49), with results maintained at follow-up. Large effects were found for anxiety, depression, and stress; moderate effects for emotional regulation and quality of life. Changes in mindfulness strongly moderated clinical outcomes. No differences emerged between meditation styles. Significant heterogeneity across trials limits the strength of conclusions.

Study at a glance

Abstract

An increasing number of studies are investigating traditional meditation retreats. Very little, however, is known about their effectiveness. To evaluate the effectiveness of meditation retreats on improving psychological outcomes in general population. A systematic review of studies published in journals or as dissertations in PSYCINFO, PUBMED, CINAHL or Web of Science from the first available date until October 22, 2016. A total of 20 papers (21 studies, N=2912) were included. Effect-size estimates of outcomes combined suggested that traditional meditation retreats are moderately effective in pre-post analyses (n=19; Hedge's g=0.45; 95% CI [0.35, 0.54], p<0.00001) and in analyses comparing retreats to controls (n=14; Hedge's g=0.49; 95% CI [0.36, 0.61], p<0.00001). Results were maintained at follow-up. No differences were observed between meditation styles. Results suggested large effects on measures of anxiety, depression and stress, and moderate effects on measures of emotional regulation and quality of life. As to potential mechanisms of actions, results showed large effects on measures of mindfulness and compassion, and moderate effects on measures of acceptance. In addition, changes in mindfulness levels strongly moderated clinical effect sizes. However, heterogeneity was significant among trials, probably due to differences in study designs, types and duration of the retreats and assessed outcomes, limiting therefore the implications of the results. Meditation retreats are moderately to largely effective in reducing depression, anxiety, stress and in ameliorating the quality of life of participants.