By Steven Reinberg
Many people meditate in an attempt to reduce stress and stress-related health problems. But whether this centuries-old approach to greater self-awareness has actual medical benefits isn't really known.
For this study, published online Jan. 6 in JAMA Internal Medicine, researchers reviewed 47 prior studies that looked at meditation's effect on various conditions that included substance abuse, eating habits, sleep, pain and weight in addition to depression and anxiety.
"The maximum strength of evidence we found was moderate for anxiety, depression and pain; low for some others and insufficient for the bulk of outcomes we evaluated," said lead researcher Dr. Madhav Goyal, an assistant professor of medicine. He noted, however, that few trials included people with a clinical diagnosis of anxiety or depression.
Meditation, said Goyal, "is an active training of the mind to increase awareness, and different meditation programs approach this in different ways." The type that looked most promising -- mindful meditation -- emphasizes acceptance of feelings and thoughts without judgment and relaxation of body and mind. It's typically practiced 30 to 40 minutes a day.
One expert welcomed the analysis.
"This is a useful summary of the current state of meditation research in medicine," said Tony Tang, an adjunct professor in the department of psychology at Northwestern University in Evanston, Ill.
However, popular mantra-based meditation (including Transcendental Meditation) did not show any benefit over placebo, and it appeared no better than any other active treatments on any measures, he said.
"So, while somewhat positive, these results are probably disappointing for meditation enthusiasts," Tang said.
The analysis included 3,515 participants, many of whom received about 30 to 40 hours of training in mindful meditation.
"We found about a 5 to 10 percent improvement in anxiety symptoms compared to placebo groups," Goyal said. "For depression, we found a roughly 10 to 20 percent improvement in depressive symptoms compared to the placebo groups. This is similar to the effects of antidepressants in similar populations."
Evidence was also moderately strong that meditation programs may reduce pain. "There weren't as many trials evaluating chronic pain, and so we don't understand what kinds of pain this type of meditation may be most useful for," Goyal added.
Still, for all its promise, meditation isn't a cure-all. There was little or no evidence of any benefit on positive mood, attention, substance abuse, eating habits, sleep and weight, the researchers say.
On the plus side, Goyal pointed out no harmful side effects were associated with meditating, and you can practice meditation along with other treatments you're receiving.
"In the context of Eastern traditions, the meditation programs that were tested were comparatively short, lasting about eight weeks, and provided relatively small doses of meditation training," Goyal said. "So, we don't know if more meditation practice would result in larger benefits, and this needs to be tested in future research"
Another expert agreed.
"It appears that for all forms of meditation, more time spent meditating will yield larger effects," said Simon Rego, director of psychology training at Montefiore Medical Center/Albert Einstein College of Medicine in New York City.
"In other words, meditation is a skill that requires instruction from an expert followed by regular practice in daily life, so it's possible that in many of the trials reviewed the amount of training or the dose afforded in the trials was too small, and with more time, better results would have been found," Rego explained. "Hopefully, future research will examine this hypothesis."
Over the past three decades, interest in meditation has grown tremendously in Western culture, including the health care system, Rego pointed out.
"Many mental health professionals touting the health benefits of meditation either include meditative techniques as part of their treatment packages or focus solely on teaching these techniques as a primary aim for improving mental health," he said.