Meditation, a mind-body method, employs a variety of techniques designed to facilitate the mind's capacity to affect bodily function and symptoms. An increasing number of patients are using meditation programs despite uncertainty about the evidence supporting the health benefits of meditation. We aimed to determine the efficacy and safety of meditation programs on stress-related outcomes (e.g., anxiety, depression, stress, distress, well-being, positive mood, quality of life, attention, health-related behaviors affected by stress, pain, and weight) compared with an active control in diverse adult clinical populations
We searched MEDLINE, PsycINFO, Embase, PsycArticles, SCOPUS, CINAHL, AMED, and the Cochrane Library in November 2012. We also performed manual searches.
We included randomized controlled trials with an active control that reported on the stress outcomes of interest. Two reviewers independently screened titles to find trials that reported on outcomes, and then extracted data on trial characteristics and effect modifiers (amount of training or teacher qualifications). We graded the strength of evidence (SOE) using four domains (risk of bias, precision, directness, and consistency). To assess the direction and magnitude of reported effects of the interventions, we calculated the relative difference between groups in how each outcome measure changed from baseline. We conducted meta-analysis using standardized mean differences to obtain aggregate estimates of effects with 95-percent confidence intervals (CIs). We analyzed efficacy trials separately from comparative effectiveness trials.
After a review of 17,801 citations, we included 41 trials with 2,993 participants. Most trials were short term, but they ranged from 4 weeks to 9 years in duration. Trials conducted against nonspecific active controls provided efficacy data. Mindfulness meditation programs had moderate SOE for improvement in anxiety (effect size [ES], 0.40; CI, 0.08 to 0.71 at 8 weeks; ES, 0.22; CI, 0.02 to 0.43 at 3–6 months), depression (ES, 0.32; CI, −0.01 to 0.66 at 8 weeks; ES, 0.23; CI, 0.05 to 0.42 at 3–6 months); and pain (ES, 0.33; CI, 0.03 to 0.62); and low SOE for improvement in stress/distress and mental health–related quality of life. We found either low SOE of no effect or insufficient SOE of an effect of meditation programs on positive mood, attention, substance use, eating, sleep, and weight. In our comparative effectiveness analyses, we did not find any evidence to suggest that these meditation programs were superior to any specific therapies they were compared with. Only 10 trials had a low risk of bias. Limitations included clinical heterogeneity, variability in the types of controls, and heterogeneity of the interventions (e.g., dosing, frequency, duration, technique).
Meditation programs, in particular mindfulness programs, reduce multiple negative dimensions of psychological stress. Stronger study designs are needed to determine the effects of meditation programs in improving the positive dimensions of mental health as well as stress-related behavioral outcomes.
