Researchers at Boston University School of Medicine (BUSM) and McLean Hospital have used magnetic resonance spectroscopic imaging to reveal the effects of yoga practice on brain concentrations of gamma-aminobutyric (GABA), the inhibitory neurotransmitter. Their findings suggest that yoga, and perhaps other forms of exercise, should be investigated as a complementary treatment for depression and anxiety disorders., which are commonly associated with low levels of GABA.

Eric Jensen and colleagues at Harvard Medical School used a specialist MR spectroscopic imaging technique of their own design to compare the GABA levels of eight subjects prior to and after one hour of yoga; 11 control subjects read rather than undertaking the yoga exercises. GABA levels rose by more than a quarter (27%) in the yoga group, but they saw no change in the readers.

The researchers point out that anecdotally yoga has shown promise in alleviating depression, anxiety, and even epilepsy. "Our findings clearly demonstrate that in experienced yoga practitioners, brain GABA levels increase after a session of yoga," says team member Chris Streeter. The study demonstrates that the GABA system can be influenced not only by pharmacological interventions but changes in behaviour, such as regular yoga practice. The findings could help to guide the development of new treatments for low GABA condition, adds co-author Domenic Ciraulo, who is professor and chairman of the department of psychiatry at BUSM.

Yoga, which purportedly has no deleterious side effects, could be used as an effective way to alleviate the symptoms of depression and anxiety and so has a clear public health advantage, Perry Renshaw, director of the Brain Imaging Center at Harvard-affiliated McLean Hospital, suggests.

The researchers add that yoga should now be compared to other forms of exercise to determine whether or not it is the particular nature of yoga asanas, or postures, that results in raised GABA levels, or whether it is simply an effect of any form of exercise.

The research itself was funded partly with grants from the national Institute of Drug Abuse, the National Institute on Alcohol Abuse and Alcoholism, the National Center for Research Resources, and the Gennaro Acampora Charity Trust to the Division of Psychiatry, Boston Medical Center.

Related links:

• J Alt Complement Med, 2007, 13,  419-426
• Renshaw Page

Article by David Bradley