Time trends in the effects of mindfulness-based cognitive therapy for depression: A meta-analysis.

Recent studies suggest that the effects of cognitive therapies for depression show systematic changes over time. A meta-analysis was conducted to explore the temporal development of the effect of mindfulness-based cognitive therapy (MBCT) for current depression in studies that used the Beck Depression Inventory (BDI) or the Hamilton Depression Rating Scale (HDRS) as outcome measures. A systematic search of research databases yielded 20 studies that were included in the analyses. The results showed that MBCT is effective in reducing depressive symptoms. The effect sizes of studies using the BDI or the HDRS as an outcome measure were not moderated by the time of publication. Funnel plots and the trim and fill method suggested that publication bias was low. However, the number of available studies was small, and the time period investigated relatively short. The results should therefore be considered preliminary.