Can yoga ease anxiety and depression

According to this article, the answer is yes:

Brain scans of yoga practitioners showed a healthy boost in levels of the neurotransmitter gamma-aminobutyric (GABA) immediately after a one-hour yoga session. Low brain levels of GABA are associated with anxiety and depression, the researchers said.

"I am quite sure that this is the first study that's shown that there's a real, measurable change in a major neurotransmitter with a behavioral intervention such as yoga," said lead researcher Dr. Chris Streeter, assistant professor of psychiatry and neurology at the Boston University School of Medicine.

She believes yoga could prove a useful tool to help people battling depression and anxiety disorders. "We're not advocating that they chuck their medication, but I would advise that they could use it as an adjunct and see how they are doing," Streeter said.

But is that really such big news? More from the article:

Zindel Segal, chairman of psychotherapy and a professor of psychology and psychiatry at the University of Toronto, has for years studied the use of behavioral interventions to alleviate psychological woes.

He said the Boston researchers were to be commended for using brain scan imaging technologies to investigate the effectiveness of these techniques. But he questioned why the yoga group was simply compared to a sedentary reading group and not to another movement-based group.

"Exercise itself may have some effects on GABA, so I think in this study, you'd really want that comparison," he said. Including such a control group would make it clear that it was yoga and not just an hour of physical exertion that was responsible for the brain changes.

He also pointed out that all of the people in the study were mentally healthy, and clinical depression and anxiety disorders involve more than the "daily fluctuations in stress and tension" that healthy individuals are prone to.

"We know that yoga can have a profound effect" on smoothing out life's daily ups and downs, Segal said. "But so does working out on a Stairmaster for an hour."