DURHAM, N.C. Post-holiday blues and a bitter winter season for much of the nation could send many people to the bottle this year the bottle of St. John's wort, that is.
Although this readily available and increasingly popular herbal supplement appears promising in treating depression, many questions remain about its safety and effectiveness, researchers say.
That is why physicians at Duke University Medical Center have compiled the most comprehensive analysis to date concerning the safety and efficacy of St. John's wort (Hypericum perforatum). The updated findings appear in the January 2001 issue of Public Health Nutrition, and researchers say they are based upon a rigorous, systematic review of all previous studies of St. John's wort as a treatment for major depressive disorder. "Studies done in the past two years have produced a lot of new information about St. John's wort," says Dr. Murali Doraiswamy, director of psychiatry clinical trials at Duke and senior author of the review. "Our review provides one location in which to reference all findings to date, and includes recommendations that should prove useful to health care providers and the public." Overall, studies show St. John's wort to be a promising drug for treating depression. But Doraiswamy says research shows a need for caution, especially for patients on certain medications including tetracycline, cyclosporin, protease inhibitors, digoxin, warfarin, some oral birth control medications and those used for asthma. He says there is some evidence that St. John's wort may induce certain enzymes in the liver to process those types of medications faster than usual, resulting in lower effective doses of those drugs in the body.
A number of studies are currently under way to determine the long-term effectiveness of St. John's wort, including a large NIH-funded study at Duke. Results of that study are expected later this year.