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Study: St. John's wort ineffective in severe depression

CHICAGO, Illinois (CNN) -- St. John's wort, an herb that has shown promise in treating mild to moderate depression, does not seem to work against a more severe form of the disease, according to a study being published in the Journal of the American Medical Association.

The herb worked no better than a placebo in a study of 200 adults diagnosed with major depression. In an earlier analysis of some 23 studies on St. John's wort on patients with less severe forms of the disease, the herb was found to be significantly superior to a placebo and just as effective as standard antidepressant drugs.

But Dr. Richard Shelton, a co-author of the new study, said earlier studies had serious limitations, and he recommended against using St. John's wort at all until further studies could be done.

"I would like to see people with mild depression studied, and see if it works in those folks. If it works, that would be great," said Shelton, a professor in the department of psychiatry at Vanderbilt University.

The study was funded partly by the National Institutes of Mental Health and partly by Pfizer Incorporated, which makes Zoloft, the most commonly prescribed anti-depression drug in the United States. It had $2.14 billion in sales last year.

But it doesn't seem to matter whether doctors recommend using St. John's wort or not -- it appears to have become a popular self-treatment for depression without the help of physicians.

One psychiatrist said nearly half his patients tried the herb before coming to him for help.

"Even if only 10 percent of all depressed subjects have tried St. John's wort, that would still make it about a million people in the U.S. alone," said the psychiatrist, Dr. P. Murali Doraiswamy, director of psychiatry clinical trials at Duke University Medical Center.

The journal study said the herb appears to be safe. However, the National Institutes of Health said research has shown that it may interfere with the effectiveness of several drugs, including protease inhibitors used to treat HIV, cyclosporine and other immunosuppressant drugs, cholesterol-lowering medications, cancer medications, seizure drugs, blood thinners and birth control pills.

Robert McCaleb, president of the Herb Research Foundation, said he wondered if perhaps the funding source for the study influenced the finding that the herb was ineffective against depression.

"I don't want to accuse anyone of conspiracy here, but I'm sure the results don't displease [Pfizer]," McCaleb said.

In the article, the authors note that Pfizer representatives were involved in the design and preparation of the study but not the analysis and interpretation of the results.

"When we provide unrestricted educational grants, they're exactly that," said Celeste Torello, a spokeswoman for Pfizer.

At the time the study was done, Pfizer also sold St. John's wort, but the company stopped selling herbs last year because it wasn't profitable, according to Meghan Marschall, a spokeswoman for Pfizer.

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Journal of the American Medical Association
National Institute of Mental Health
Herb Research Foundation
Pfizer Inc.

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4:30pm ET, 4/16

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