Despite widespread scientific and popular interest in mindfulness-based interventions, questions regarding the empirical status of these treatments remain. We sought to examine the efficacy of mindfulness-based interventions for clinical populations on disorder-specific symptoms. To address the question of relative efficacy, we coded the strength of the comparison group into five categories: no treatment, minimal treatment, non-specific active control, specific active control, and evidence-based treatment. A total of 142 non-overlapping samples and 12,005 participants were included. At post-treatment, mindfulness-based interventions were superior to no treatment (d=0.55), minimal treatment (d=0.37), non-specific active controls (d=0.35), and specific active controls (d=0.23). Mindfulness conditions did not differ from evidence-based treatments (d=-0.004). At follow-up, mindfulness-based interventions were superior to no treatment conditions (d=0.50), non-specific active controls (d=0.52), and specific active controls (d=0.29). Mindfulness conditions did not differ from minimal treatment conditions (d=0.38) and evidence-based treatments (d=0.09). Effects on specific disorder subgroups showed the most consistent evidence in support of mindfulness for depression, pain conditions, smoking, and addictive disorders. Results support the notion that mindfulness-based interventions hold promise as evidence-based treatments.

Despite widespread scientific and popular interest in mindfulness-based interventions, questions regarding the empirical status of these treatments remain. We sought to examine the efficacy of mindfulness-based interventions for clinical populations on disorder-specific symptoms. To address the question of relative efficacy, we coded the strength of the comparison group into five categories: no treatment, minimal treatment, non-specific active control, specific active control, and evidence-based treatment. A total of 142 non-overlapping samples and 12,005 participants were included. At post-treatment, mindfulness-based interventions were superior to no treatment (d = 0.55), minimal treatment (d = 0.37), non-specific active controls (d = 0.35), and specific active controls (d = 0.23). Mindfulness conditions did not differ from evidence-based treatments (d = -0.004). At follow-up, mindfulness-based interventions were superior to no treatment conditions (d = 0.50), non-specific active controls (d = 0.52), and specific active controls (d = 0.29). Mindfulness conditions did not differ from minimal treatment conditions (d = 0.38) and evidence-based treatments (d = 0.09). Effects on specific disorder subgroups showed the most consistent evidence in support of mindfulness for depression, pain conditions, smoking, and addictive disorders. Results support the notion that mindfulness-based interventions hold promise as evidence-based treatments.

BackgroundDespite an exponential growth in research on mindfulness-based interventions, the body of scientific evidence supporting these treatments has been criticized for being of poor methodological quality.ObjectivesThe current systematic review examined the extent to which mindfulness research demonstrated increased rigor over the past 16 years regarding six methodological features that have been highlighted as areas for improvement. These feature included using active control conditions, larger sample sizes, longer follow-up assessment, treatment fidelity assessment, and reporting of instructor training and intent-to-treat (ITT) analyses.Data sourcesWe searched PubMed, PsychInfo, Scopus, and Web of Science in addition to a publically available repository of mindfulness studies.Study eligibility criteriaRandomized clinical trials of mindfulness-based interventions for samples with a clinical disorder or elevated symptoms of a clinical disorder listed on the American Psychological Association’s list of disorders with recognized evidence-based treatment.Study appraisal and synthesis methodsIndependent raters screened 9,067 titles and abstracts, with 303 full text reviews. Of these, 171 were included, representing 142 non-overlapping samples.ResultsAcross the 142 studies published between 2000 and 2016, there was no evidence for increases in any study quality indicator, although changes were generally in the direction of improved quality. When restricting the sample to those conducted in Europe and North America (continents with the longest history of scientific research in this area), an increase in reporting of ITT analyses was found. When excluding an early, high-quality study, improvements were seen in sample size, treatment fidelity assessment, and reporting of ITT analyses.Conclusions and implications of key findingsTaken together, the findings suggest modest adoption of the recommendations for methodological improvement voiced repeatedly in the literature. Possible explanations for this and implications for interpreting this body of research and conducting future studies are discussed.

Objective: The present study reports on the long-term effects of a mindfulness-based stress reduction (MBSR) program for adult survivors of childhood sexual abuse. Method: Of the study participants, 73% returned to the clinic for a single-session follow-up assessment of depression, posttraumatic stress disorder (PTSD), anxiety, and mindfulness at 2.5 years. Results: Repeated measures mixed regression analyses revealed significant long-term improvements in depression, PTSD, anxiety symptoms, and mindfulness scores. The magnitude of intervention effects at 128 weeks ranged from d = .5 to d = 1.1. Conclusion: MBSR may be an effective long-term treatment for adults who have experienced childhood sexual abuse. Further investigation of MBSR with this population is warranted given the durability of treatment effects described here. C 2014 Wiley Periodicals, Inc. J. Clin. Psychol. 00:1-9, 2014.

Simpson, T.L. (in press). Mindfulness-based cognitive therapy for the treatment of current depressive symptoms: A meta-analysis. Cognitive Behaviour Therapy.