Study: St. John's Wort Doesn't Help Depression

In what is claimed to be the largest clinical trial performed to date on the popular herbal supplement St. John's wort, researchers have found it to be ineffective for major depression.

Duke University Medical Center researchers found the herb to be no more effective than a placebo for the treatment of a moderately severe form of major depression, which is one of the most common forms of depression.

In the study, published in the April 10 issue of the Journal of the American Medical Association, researchers used the antidepressant sertraline, trade name Zoloft, as a "control" against St. John's wort. Antidepressants such as Zoloft have been found to be effective in treating several forms of depression.

"Major depression is treatable, but this research suggests that major depression of at least moderate severity should not be treated with St. John's wort," said Dr. Jonathan Davidson, director of the Anxiety and Traumatic Stress Program at Duke and lead researcher.

"Rather than self-medicate with an over-the-counter medication or supplement, patients are strongly advised to consult an appropriate health-care provider to assess the best treatment for a depressive episode," Davidson said.

Previous studies about St. John's wort and other herbal remedies have been inadequate -- and dangerous, said Dr. Robert Califf, director of the Duke Clinical Research Institute.

"As long as these types of products remain available to the public without the protection of adequate, controlled and unbiased studies, taking them is like playing Russian roulette with your health," Califf said.

"More people are turning to St. John's wort as a treatment for their depressive symptoms than ever before, and the majority of them do so without consulting a physician," Davidson said. He said more studies are needed on the effects of herbal supplements and prescription drugs for the treatment of depression.

Previous studies of the herb have not clearly characterized the types of depression that might respond to this treatment. The Duke-led study monitored 340 participants diagnosed with major depression at 12 study sites for eight weeks to six months.

The results showed that St. John's wort had no better effects than a placebo.

Herbal supplements have grown in popularity during the last decade as more consumers look for "natural" medicines. However, just because a product claims to be "natural" does not mean it is safe, Davidson said. A product as gentle as baby aspirin can be toxic at high doses, he said.

"Just because St. John's wort was found to be ineffective for this type of depression does not mean it is harmless to the body," Califf said. "Several studies have shown that St. John's wort interacts dangerously with several medications such as those used to treat HIV/AIDS, certain cardiac conditions and even those that keep the body from rejecting organs after transplant."

Depression, if not properly treated, can cause serious complications. "It is very important to treat it early and effectively," Davidson said.

Major depression affects approximately 9.9 million American adults age 18 and older in any given year and is a leading cause of disability in the United States, according to the National Institute of Mental Health. If left untreated, this type of depression can lead to symptoms such as significant weight loss or gain, sleep disturbances, agitation or unusual slowness, fatigue or loss of energy, feelings of worthlessness or guilt, lack of concentration, or recurrent thoughts of death or suicide.

In 1998, sales of the herb in the United States were estimated to be $210 million, with that number expected to rise as more people turn to alternative types of medicines to treat disorders like depression, according to a previous study conducted at Duke.

The study was funded by the National Center for Complementary and Alternative Medicine, the NIMH and the Office of Dietary Supplements, all divisions within the National Institutes of Health.

Davidson holds stock in several drug manufacturing companies, including Pfizer, American Home Products, GlaxoSmithKline, Proctor and Gamble and Triangle Pharmaceuticals.