Advance Zen Buddhist meditation may help treat depression, attention deficit disorder and anxiety, among other maladies, according to a recent study by Emory University neuroscientists.

Mental illnesses such as obsessive-compulsive disorder and depression are characterized in part by "excessive rumination" or runaway thoughts, said Giuseppe Pagnoni, a neuroscientist at Emory in Atlanta.

Zen meditators show an enhanced ability to control their mind's focus, and disentangle it from distracting or harmful preoccupations, Pagnoni argues. His paper, "Thinking about Not-Thinking: Neural Correlates of Conceptual Processing during Zen Meditation," was published by the online journal PLoS ONE in September.

Unlike other forms of meditation -- for example, imagining yourself on a tropical beach -- Zen discourages mental vacations and "prescribes a vigilant attitude" toward one's present surroundings, as Pagnoni says. By focusing on the here and now, practitioners are less likely to get carried away, according to Buddhist teaching.

Using brain imaging scans, the Emory study compared 12 people with no meditation experience with a dozen who had practiced Zen meditation daily for at least three years. Pagnoni and his team monitored brain activity as the subjects were asked to distinguish between words or nonsensical jumbles of letters that periodically flashed on a screen before them. After the letters disappeared, the subjects were asked to focus on their breath -- a common Zen meditation practice -- as quickly as possible.

The brain scans showed that Zen meditators were able to stop their minds from wandering and return to focusing on their breathing much quicker than the non-meditators, according to Pagnoni.

"The regular practice of meditation may enhance the capacity to limit the influence of distracting thoughts," Pagnoni told the online journal LiveScience.com.

Scientific interest in the therapeutic effects of Buddhist meditation has exploded in recent years, especially with the development of cutting-edge machines that can map neural activity.

The National Institutes of Health is financing more than 50 studies testing meditation, or "mindfulness techniques," according to published reports. Studies suggest daily meditation can alleviate symptoms from hypertension, depression and stress as well as help the immune system fight off disease, according to psychotherapists.

In the last 30 years, Buddhist ideas and techniques have permeated every branch of psychotherapy, said Dr. Mark Epstein, author of "Psychotherapy without the Self: A Buddhist Perspective."

While meditation is useful in many ways, Epstein said, he rarely assigns it to patients in his New York City practice.

"The more entrenched the condition is -- like severe OCD or major depression, the less helpful meditation will be," Epstein said. "We should not talk about meditation as a panacea for all that stuff because it's just setting people up for disappointment."

Still, Epstein said clinical work like Pagnoni's on the effect of meditation is important.

"It's been very useful to have it documented in a material way," Epstein said, "because that's what people believe in our culture."