Despite the popularity of MBT, relatively few clinical trials have specifically examined this treatment in anxiety disorders and depression. However, a relatively large number of studies have examined changes in anxiety and depressive symptoms in a range of psychiatric and medical disorders. We decided to examine all available studies that reported changes in anxiety and depressive symptoms during the course of MBT. As a result, the included studies differ in the disorders targeted and also in their methodological quality. However, the Jadad scores did not moderate the effect size estimate. Furthermore, it should be noted that the quality and homogeneity of the studies included in the meta-analysis was considerably better than that of studies used for other recently published meta-analytic reviews of established but poorly validated psychodynamic interventions (Leichsenring & Rabung, 2008; Leichsenring, Rabung, & Leibing, 2004). Moreover, the fail-safe N and funnel plot analyses suggest that the results for uncontrolled pre-post effect sizes are robust and unlikely to be the effect of a publication bias or number of treatment sessions and were maintained over an average 27 week follow-up period (median: 12 weeks).
