Having traveled in and out of meditation circles over the years, I’ve seen much hype, placebo effect and outright self-deception. I’ve also experienced some benefits, but not nearly as much as my naive, idealist mind had hoped for — as it likewise hoped for in Christianity, Acupuncture, Marxism, Homeopathy and my many other adventures. (see my other follies here)
In January 2014, researchers at Johns Hopkins University Evidence-based Practice Center in Baltimore, MD (where I did my MPH), have done a large meta-analysis of studies on the effectiveness of meditation. They reviewed 17,801 citations and included 41 trials with 2,993 participants.
Article here: Meditation Programs for Psychological Stress and Well-being: A Systematic Review and Meta-analysis. January 2014. See this Jama article for an updated version.
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).