Researchers from Johns Hopkins University performed a meta-analysis to determine the effects of meditation practice in improving stress related outcomes (anxiety, depression, stress/distress, positive mood, mental health-related quality of life, attention, substance use, eating habits, sleep, pain, and weight) in various adult clinical populations.

They identified randomized clinical trials with active controls for placebo effects from MEDLINE, PsycINFO, EMBASE, PsycArticles, Scopus, CINAHL, AMED, the Cochrane Library, and hand searches.
Strength of evidence was graded using 4 domains (risk of bias, precision, directness, and consistency) and magnitude and direction of effect were determined by calculating the relative difference between groups in the change from baseline.

When possible, meta-analyses were conducted using standardized mean differences to obtain aggregate estimates of effect size with 95% confidence intervals.

There were 47 trials with 3515 participants which qualified for study. Mindfulness meditation programs had

  • moderate evidence of improved anxiety at 8 weeks and at 3-6 months,
  • improved depression at 8 weeks and 0.23 at 3-6 months,  
  • improved pain and
  • low evidence of improved stress/distress and mental health-related quality of life
  • low evidence or insufficient evidence of any effect on positive mood, attention, substance use, eating habits, sleep and weight.
  • no evidence that meditation programs were better than any active treatment (ie, drugs, exercise, and other behavioral therapies).

The investigators conclude that health providers and clinicians should be aware that meditation programs can result in small to moderate reductions of multiple negative dimensions of psychological stress.
And they recommend stronger study designs to determine the effects of such programs in improving mental health and stress-related behavior.

Citation: Goyal M1, Singh S1, Sibinga EM2, Gould NF3, Rowland-Seymour A1, Sharma R4, Berger Z1, Sleicher D3, Maron DD4, Shihab HM4, Ranasinghe PD1, Linn S4, Saha S2, Bass EB5, Haythornthwaite JA3. Meditation programs for psychological stress and well-being: a systematic review and meta-analysis. JAMA Internal Medicine. 2014 Mar;174 (3): pages 357-68.