Mindfulness-based interventions for depressive rumination: Review and meta-analysis

Perestelo-Perez, L., et al. (2017). Mindfulness-based interventions for the treatment of depressive rumination: Systematic review and meta-analysis. International Journal of Clinical and Health Psychology17(3), 282-295.

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.

Results: A meta-analysis of the effect of the intervention compared to usual care showed a significant and moderate reduction of ruminative thoughts. 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.

Interventions for psychiatric disorders

Goldberg, S. B., et al. (2018). Mindfulness-based interventions for psychiatric disorders: A systematic review and meta-analysis. Clinical psychology review, vol. 59, pp. 52-60, https://doi.org/10.1016/j.cpr.2017.10.011. Full text.

Highlights —

•  We examined the relative efficacy of mindfulness-based interventions on clinical symptoms of psychiatric disorders.

•  142 randomized clinical trials were included (N = 12,005 participants). Control conditions were coded on a five-tier system.

•  At post-treatment, mindfulness interventions were equivalent to evidence-based treatments and superior to other comparisons.

•  At follow-up, mindfulness interventions were equivalent to minimal and evidence-based treatments and superior to others.

•  The most consistent evidence for mindfulness-based interventions was seen for depression, pain, smoking, and addictions.

Effectiveness of meditation retreats: meta-analysis

Khoury, B., at al. (2017). Effectiveness of traditional meditation retreats: A systematic review and meta-analysis. Journal of psychosomatic research92, 16-25, https://doi.org/10.1016/j.jpsychores.2016.11.006. Taken from the Abstract.

Background. An increasing number of studies are investigating traditional retreats. Very little, however, is known about their effectiveness.

Objective. To evaluate the effectiveness of meditation retreats on improving in general population. A total of 20 papers (N = 2912) were included.

Results suggested large effects on measures of anxiety, depression, 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. 

Meditation and PTSD

Hilton, L., et al. (2017). Meditation for posttraumatic stress: Systematic review and meta-analysis. Psychological Trauma: Theory, Research, Practice, and Policy9(4), 453. From the Abstract.

Objective: We conducted a systematic review and meta-analysis that synthesized evidence from randomized controlled trials of meditation interventions to provide estimates of their efficacy and safety in treating adults diagnosed with posttraumatic stress disorder (PTSD).

Results: In total, 10 trials on meditation interventions for PTSD with 643 participants met inclusion criteria. Across interventions, adjunctive meditation interventions of mindfulness-based stress reduction, yoga, and the mantram repetition program improve PTSD and depression symptoms compared with control groups, but the findings are based on low and moderate quality of evidence.

Effects were positive but not statistically significant for quality of life and anxiety, and no studies addressed functional status. The variety of meditation intervention types, the short follow-up times, and the quality of studies limited analyses.

Conclusions: Meditation appears to be effective for PTSD and depression symptoms, but in order to increase confidence in findings, more high-quality studies are needed on meditation as adjunctive treatment with PTSD-diagnosed participant samples large enough to detect statistical differences in outcomes.

Beneficial for asthma?

Paudyal, P., et al. (2018). Meditation for asthma: Systematic review and meta-analysis. Journal of Asthma55(7), 771-778, https://doi.org/10.1080/02770903.2017.1365887. 

From the AbstractOur review suggests that there is some evidence that meditation is beneficial in improving quality of life in asthma patients. As two out of four studies in our review were of poor quality, further trials with better methodological quality are needed to support or refute this finding.

Meditation and prosocial behaviors (review & meta-analysis)

Kreplin, U., Farias, M., & Brazil, I. A. (2018). The limited prosocial* effects of meditation: A systematic review and meta-analysis. Scientific reports, vol. 8, no. 1, pp. 2403, DOI:10.1038/s41598-018-20299-z. Full text.

 Abstract. Many individuals believe that meditation has the capacity to not only alleviate mental-illness but to improve prosociality. This article systematically reviewed and meta-analysed the effects of meditation interventions on prosociality in randomized controlled trials of healthy adults.

Five types of social behaviours were identified: compassion, empathy, aggression, connectedness and prejudice. Although we found a moderate increase in prosociality following meditation, further analysis indicated that this effect was qualified by two factors: type of prosociality and methodological quality.

Meditation interventions had an effect on compassion and empathy, but not on aggression, connectedness or prejudice. We further found that compassion levels only increased under two conditions: when the teacher in the meditation intervention was a co-author in the published study; and when the study employed a passive (waiting list) control group but not an active one.

Contrary to popular beliefs that meditation will lead to prosocial changes, the results of this meta-analysis showed that the effects of meditation on prosociality were qualified by the type of prosociality and methodological quality of the study. We conclude by highlighting a number of biases and theoretical problems that need addressing to improve quality of research in this area.

* Prosocial behavior, or “voluntary behavior intended to benefit another”, is a social behavior that “benefit[s] other people or society as a whole”, “such as helping, sharing, donating, co-operating, and volunteering” (Wikipedia).

Is meditation associated with altered brain structure?

Fox, K. C., et al. (2014). Is meditation associated with altered brain structure? A systematic review and meta-analysis of morphometric neuroimaging in meditation practitioners. Neuroscience & Biobehavioral Reviews, no. 43, pp. 48-73, https://doi.org/10.1016/j.neubiorev.2014.03.016. Full text.

From the Abstract. Numerous studies have begun to address how the brain’s gray and white matter may be shaped by meditation. This research is yet to be integrated, however, and two fundamental questions remain: Is meditation associated with altered brain structure? If so, what is the magnitude of these differences?

To address these questions, we reviewed and meta-analyzed 123 brain morphology differences from 21 neuroimaging studies examining ∼300 meditation practitioners. Anatomical likelihood estimation meta-analysis found eight brain regions consistently altered in meditators, including areas key to meta-awareness (frontopolar cortex/BA 10), exteroceptive and interoceptive body awareness (sensory cortices and insula), memory consolidation and reconsolidation (hippocampus), self and emotion regulation (anterior and mid cingulate; orbitofrontal cortex), and intra- and interhemispheric communication (superior longitudinal fasciculus; corpus callosum). 

Publication bias and methodological limitations are strong concerns, however. Further research using rigorous methods is required to definitively link meditation practice to altered brain morphology.

For an update by the same authors, see “Alterations in the structure of the brain — review & implications.”