Kava in generalized anxiety disorder: three placebo-controlled trials

In this study, we evaluated the efficacy and safety of kava kava (Piper methysticum) in generalized anxiety disorder. Data were analyzed from three randomized, double-blind, placebo-controlled trials of kava, including one study with an active comparator (venlafaxine), in adult outpatients with DSM-IV generalized anxiety disorder. The pooled sample (n=64) included the following number of participants: kava, n=28; placebo, n=30; and venlafaxine, n=6. Given the comparability of the study designs, the data comparing kava and placebo were then pooled for further efficacy and safety analyses. No significant differences were observed between the treatment groups in any of the trials. In the pooled analyses, no effects were found for kava, while a significant effect in favor of placebo was observed in participants with higher anxiety at baseline. No evidence of hepatotoxicity was found with kava, and all of the treatments were well tolerated. Findings from these three controlled trials do not support the use of kava in DSM-IV generalized anxiety disorder.