The results obtained are robust and are maintained at follow-up.

When compared with other treatments, we obtained a smaller effect (Hedge's g = .33).

We obtained Hedge's g = .53 in waitlist controlled studies, .55 in pre-post studies.

It includes 209 studies enrolling 12,145 participants with a variety of disorders.

We conducted a meta-analysis to provide a review of mindfulness-based therapy.

Abstract

Background Mindfulness-based therapy (MBT) has become a popular form of intervention. However, the existing reviews report inconsistent findings.

Objective To clarify these inconsistencies in the literature, we conducted a comprehensive effect-size analysis to evaluate the efficacy of MBT.

Data sources A systematic review of studies published in journals or in dissertations in PubMED or PsycINFO from the first available date until May 10, 2013.

Review methods A total of 209 studies (n = 12,145) were included.

Results Effect-size estimates suggested that MBT is moderately effective in pre-post comparisons (n = 72; Hedge's g = .55), in comparisons with waitlist controls (n = 67; Hedge's g = .53), and when compared with other active treatments (n = 68; Hedge's g = .33), including other psychological treatments (n = 35; Hedge's g = .22). MBT did not differ from traditional CBT or behavioral therapies (n = 9; Hedge's g = − .07) or pharmacological treatments (n = 3; Hedge's g = .13).