Study Dismissing St. John’s Wort Raises More Questions
Definitive though it may have sounded, the recent federal study of St. John’s wort still hasn’t answered all the questions about the herb’s effectiveness in treating depression.
Researchers reported last week that the herb failed to alleviate moderately severe cases of the illness, which can interfere with work, sleep, eating habits and personal relationships. The $6-million study, begun in 1997, was the first multi-center clinical trial funded by the National Center for Complementary and Alternative Medicine, and the results were widely anticipated.
But the research didn’t deliver a verdict on whether the popular herb can ease milder forms of the disorder. And study critics, including the American Herbal Products Assn., the National Nutritional Foods Assn. and the American Botanical Council, fear that consumers will come away from the latest findings with the impression that St. John’s wort is useless for all depression.
In the study, which was reported in the April 10 issue of the Journal of the American Medical Assn., researchers studied 340 people whose depression affected their daily activities, but who weren’t suicidal. After eight weeks, all the participants showed similar results on two major measures of improvement--better scores on a depression scale and being symptom-free--regardless of whether they were given extracts of the plant Hypericum perforatum (St. John’s wort), the prescription antidepressant sertraline (Zoloft) or a placebo.
The lead researcher, Dr. Jonathan R.T. Davidson, a psychiatry professor at Duke University Medical Center in Durham, N.C., said that on some secondary measures, patients taking Zoloft did a little better than the other patients. But the small differences among the treated and untreated groups suggest that St. John’s wort wasn’t effective, he said.
Although it will take a series of studies to provide a definitive answer, he said, “so far, there is no evidence that St. John’s wort is a leading candidate for the treatment of moderately severe major depression.”
The results came a year after another JAMA study, funded by a major pharmaceutical firm, found St. John’s wort to be no better than a placebo in treating major depression. Complementary health experts attacked that study as well, saying the patients selected might have been among those who just don’t respond to any treatment.
Smaller studies have suggested the herb’s effectiveness in milder forms of depression, and experts say more definitive data on that issue is needed.
The center’s director, Dr. Stephen E. Straus, said the decision to first study use of the herb in more severe forms of depression before studying its use in milder illness was based on public health interests. People with more debilitating depression shouldn’t self-medicate, he said, but instead should seek professional guidance and opt for established treatments, such as medication or psychotherapy. Straus and depression experts hope that, by hearing that St. John’s wort would be unlikely to ease their depression, those with severe forms might be more likely to seek help.
Straus said the study should put to rest questions about the herb’s value in such cases.
“In science, people have a hard time coming to closure and saying that we have absolutely enough data,” he said. “We have about 1,500 herbs to study. At some point, now that there have been two very good studies, I think we should move on.”
The herb’s effect on milder forms of the disorder will soon be examined in a $4-million federal study at the Harvard-affiliated Massachusetts General Hospital and two other centers.
But some study critics say much is still unknown about the herb’s effectiveness.
“My feeling is we really have no data that it’s not good for severe depression,” said Jerry Cott, a psychopharmacologist who worked on the initial design for the study. Because study patients who got St. John’s wort or Zoloft did no better the placebo patients, he said, it’s hard to tell whether the study failed or the treatment failed.
