By Richard N. Podell, M.D.
Kava (Piper methysticum) is a newly popular herbal treatment for anxiety. Also known as kava-kava, asava pepper or intoxicating pepper, the plant has an exotic background. Part of the traditional religious and social ceremonies in Polynesia and other Pacific islands, kava is prized for its ability to soothe the worried mind. It is reputed to be nonaddictive and relatively nontoxic. Hence the recent interest in using kava to treat chronic anxiety and stressrelated problems.
The largest, most carefully conducted study of kava’s antianxiety effects was published in the January 1997 Pharmacopsychiatry and shows kava is effective, but works slowly. Its benefit became clear only after eight weeks of treatment.
The European multicenter study was conducted in Germany. Researchers from the department of psychiatry at Jena University used WS 1490, a fat-soluble kava extract manufactured in Germany. Subjects were 101 outpatient volunteers suffering from generalized anxiety, obsessive-compulsive disorder or phobias. Each subject received 24 weeks of treatment with either 100 mg kava three times daily (standardized to contain 70 percent kava lactone, a formulation available commercially) or a placebo. Several standard psychological tests, including the Hamilton Anxiety Scale (HAMA), were used to measure anxiety.
After eight weeks, subjects taking kava showed a statistically significant improvement compared to those on placebo. This difference increased further at weeks 12 and 24. By 24 weeks the average HAMA score for kava, treated subjects had decreased dramaticallyfrom 30,7 before treatment to 9.9. The researchers rated 53 percent of the kava group as "very much improved" vs. 30 percent for placebo. Adverse reactions were rare.
This is the first long-term trial testing kava to treat anxiety. Two previous studies of the same WS 1490 extract showed benefits compared to placebo after four weeks of treatment. One study treated people with anxiety, the other addressed women with symptoms associated with menopause. A third study, lasting six weeks, found WS 1490 to be as effective as two different ValiumTm-type tranquilizers.
Together these studies provide strong support for kava’s effectiveness as an antianxiety treatment. Most important, kava seems to be relatively safe-probably safer than most antianxiety drugs. For example, recent research found that kava did not decrease reaction time or ability to concentrate.
? Given kava’s reputation as a sedative, be wary about using it until more studies confirm it does not compromise concentration.
? We don’t know much about kava’s interaction with medicines or other herbs that affect the central nervous system such as St.-John’s Wort (Hypericum perforatum). Assume, until proven otherwise, that there might be interactions with alcohol, prescription tranquilizers and natural sedatives such as valerian (Valeriana officinalis).
? Pacific islanders who use kava sometimes develop a skin rash that might be caused by kava. However, Western herbalists do not report many skin problems in conjunction with kava use. Some speculate the rash results from drinking kava juice, not with taking the standardized extract. Kava may also cause difficulties focusing and temporary dilation of the pupils.
? The beneficial effect of kava was shown using one standardized extract, WS 1490. Other kava brands may not do as well.
? Anyone whose anxiety is serious enough to justify<