April 25, 2001
INTELIHEALTH FEATURE -
By Lisa Ellis InteliHealth Staff Writer A large new study raises questions about the effectiveness of the popular herbal product St. John's wort in treating severe depression.
The study, published in the April 18, 2001, issue of the Journal Of The American Medical Association (JAMA), contrasts with more than two dozen earlier studies that found the herb helpful, generally for mild to moderate depression.
Researchers from 11 medical centers across the United States were involved in the new study, which looked at 200 patients with major depression, the most serious type.
The researchers found that more patients who took St. John's wort had relief of symptoms than did the patients who were given sugar pills, but that the difference was too small to be meaningful. In contrast, numerous earlier studies have found that St. John's wort works significantly better than a placebo against depression and as well as some prescription antidepressant medicines, generally with fewer side effects.
"The results from the current study call into question the findings of the prior research reports," wrote the authors, led by Richard C. Shelton, M.D., of Vanderbilt University. They criticized the research methods of most of the earlier studies.
The study was funded by a research grant from Pfizer Inc., a pharmaceutical company that manufactures antidepressant medications and St. John's wort.
Michael Jenike, M.D., a Harvard Medical School professor of psychiatry who has used St. John's wort for years with some patients, said the study was helpful but not conclusive.
"It's a good study, a large number of subjects, so my conclusion would be that if St. John's wort works in a large number of people it's not a huge effect," he said. "That doesn't mean it wouldn't work in individuals."
In the JAMA study, which the authors described as the first of its type and scale in the United States, 200 patients who had been depressed an average of two years were enrolled after evaluation using standard depression scales, including a score of at least 20 on the Hamilton Rating Scale for Depression, investigators reported.
Participants were assigned randomly to receive one 300-milligram tablet three times a day of either St. John's wort or a placebo. The dosage was increased to four tablets daily if patients did not improve much by the fourth week of the eight-week study. The study did not measure St. John's wort against any antidepressant medication.
In all, 80 people receiving St. John's wort and 87 receiving placebo completed the study. Of this group, 32.9 percent who took St. John's wort and 20.7 percent of the placebo group showed at least a 50 percent improvement in symptoms. This difference is not statistically significant, the investigators said. In other words, although the study group was comparatively large, it was still not large enough to suggest that the results would be borne out across the population as a whole.
About 20.3 percent of the St. John's group and 10.3 percent of the placebo group had an even greater reduction of symptoms, described as "remission." This difference also is not considered significant.
The researchers in the JAMA study also analyzed 23 earlier studies and found "pervasive and serious" problems with the research methods. These problems included small size, relatively short duration, failure to use standard depression measurements and diagnostic procedures in screening participants, use of inexperienced investigators, lack of a placebo control group, use of inadequate doses of the antidepressants studied, and failure to mask the taste of St. John's wort to ensure that participants did not know what medicine they received, the authors wrote.
People who would like to see better studies of St. John's wort are looking forward to the results of a current multi-center study financed by the National Institutes of Mental Health that will measure its effectiveness against major depression.
Dr. Jenike acknowledged that most earlier studies of St. John's wort have been "not great." Many are from Germany, where the herb often is prescribed by doctors as an antidepressant.
Dr. Jenike said the current study had a few flaws as well. "Probably not having a drug-comparison group was the biggest flaw," he said. He also noted that the study lasted only eight weeks, "and most of the studies show it takes longer than that to help depression."
In addition, he pointed out that the participants had been depressed for about two years. "They were a pretty ill group in terms of longevity."
Researchers in the current study did attempt to find out whether St. John's wort worked better on the less severely depressed patients in their study group. When they examined just that group, the differences between the effects of St. John's wort and placebo again were not significant.
About 41 percent of the herbal group reported headaches as a side effect, compared with 25 percent of the placebo group. Only 1 percent of both groups discontinued participation because of adverse effects.
Dr. Jenike said that more study is needed on St. John's wort, but that it may be an option for people who prefer an herbal product and are not suicidal or severely impaired by their depression. "It seems like it may help people with mild depression, but again, if you gave them a placebo pill some of them would be helped," he said.
Used with permission of the copyright owner. All rights reserved. This article is not intended to provide advice on personal medical matters or to substitute for consultation with a physician.
