Natural Anxiety Treatment May Work
Feb. 25, 2000 (Lake Tahoe, Calif.) -- Kava, an extract from the root of the pepper plant Piper methysticum, has come a long way from the South Pacific, where it has been a staple of traditional medicine for centuries. Today in the U.S., kava is an herbal best seller, often taken for its relaxing properties. Now a review of studies from Europe and the U.S. concludes that kava is relatively effective and safe.
Max H. Pittler and Edzard Ernst of the University of Exeter in England write in the February issue of the Journal of Clinical Psychopharmacology that many studies of kava extract may have overestimated its beneficial effects. So they reviewed published studies on kava and asked kava experts to submit their research for evaluation. Pittler and Ernst focused on seven of the more carefully designed studies, three of which compared kava's effects to those of a placebo. In all three trials, kava was more effective than the sugar pill in relieving symptoms of anxiety.
Five of the seven trials reported adverse effects such as stomach complaints, restlessness, drowsiness, tremor, headache, and tiredness. But the two studies that reported no adverse effects represented 31 percent of the total number of patients tested, the authors write.
The authors pointed out several shortcomings of their research: The European medical journals might be underrepresented in the literature they searched. Researchers tend not to publish trials with negative results, particularly in journals of complementary or alternative medicine. And the sample size in most of the trials was small.
The sample size is one of several concerns of Naresh Emmanuel, assistant professor of psychiatry at the Medical University of South Carolina in Charleston, who reviewed the analysis for WebMD. He says none of the studies surveyed involved enough people to rule out the likelihood that the results were reached by chance.
Emmanuel also says that the range of anxiety symptoms in the study subjects was too diverse. "It's like saying, we'll take everybody with headaches. ... You're not looking at a unified sample," he tells WebMD.
Still, Emmanuel says, the bottom line is that the studies suggest kava is effective, and he occasionally suggests it to his patients. But he cautions people who take the supplement not to mix it with alcohol or other drugs that affect the brain, and not to do anything that requires being alert, such as driving. Also, if used for a long time, kava can cause scaling of the skin, he says.