Randomized, dose‐controlled double‐blind trial: Efficacy of an ethanolic kava (Piper methysticum rhizome) extract for the treatment of anxiety in elderly patients

Aim Kava, an aqueous drink from the roots and peeled rootstock of the plant Piper methysticum G.Forst., is renowned in Melanesia, Polynesia and Micronesia for its relaxant effect. Modern extract preparations with defined contents of kavalactones – the major active constituents – are well established as herbal medicinal products on the European market. The aim of this trial was to present data on the clinical efficacy of an ethanolic kava extract. Methods In the present double‐blind clinical trial, the differences in clinical outcome between a low dose of ethanolic kava extract (equivalent to 20 mg kavalactones daily) and a respective high dose (equivalent to 200 mg kavalactones daily) were investigated. Patients with anxiety disorders were randomized into the two groups, resulting in 33 patients in the high‐dose group and 36 patients in the low‐dose group. The study duration was 4 weeks; the primary parameter was the Hamilton anxiety (HAMA) score. Global efficacy was rated by the physician at the end of the study. Safety of application was based on the documentation of adverse events. Results The high‐dose group was statistically significantly superior to the low‐dose group on HAMA total score and its subscores for psychological and physical manifestations of anxiety ( P < 0.001), with a total improvement of −41.5% versus −13.6% relative to baseline HAMA total score on day 28. No adverse events occurred. Conclusion Kava preparations have a dose‐dependent anxiolytic effect.