Mindfulness-based interventions for the treatment of depressive rumination: Systematic review and meta-analysis.

Background/Objective: This systematic review aims to evaluate the effect of interventions based on the mindfulness and/or acceptance process on ruminative thoughts, in patients with depression. Method: Electronic searches in Medline, Embase, Cochrane Central, PsycInfo, and Cinahl until December 2016, in addition to hand-searches of relevant studies, identified eleven studies that fulfilling inclusion criteria. Results: A meta-analysis of the effect of the intervention compared to usual care showed a significant and moderate reduction of ruminative thoughts (g = -0.59, 95% CI: -0.77, -0.41; I2 = 0%). Furthermore, findings suggest that mindfulness/acceptance processes might mediate changes in rumination, and that they in turn mediate in the clinical effects of interventions. A meta-analysis of three studies that compared the intervention to other active treatments (medication, behavioral activation and cognitive-behavioral therapy, respectively) showed no significant differences. Conclusions: Mindfulness-based cognitive therapy compared to usual care, produces a significant and moderate reduction in rumination. This effect seems independent of the treatment phase (acute or maintenance) or the number of past depressive episodes, and it was maintained one month after the end of treatment. However, further controlled studies with real patients that compare the most commonly used cognitive-behavioral techniques to treat ruminative thoughts to the acceptance and mindfulness techniques are needed.