Background: Generalized anxiety disorder (GAD) is a chronic and debilitating condition characterized by persistent and overpowering anxiety. Treatment of GAD with antidepressants and benzodiazepines is only moderately effective and not free from side effects. Kava (Piper methysticum) has been explored as a potential phytotherapeutic option for GAD.
Objectives: To perform a systematic review and meta-analysis of the available evidence on Kava as a treatment for GAD.
Methods: Systematic search of English-language publications from major databases for clinical trials reporting the effects of Kava for the treatment of GAD.
Results: Twelve articles were included in this review. Evidence supporting Kava as an effective treatment for GAD was found in two placebo-controlled trials and a reference-controlled trial. One negative trial demonstrated that Kava was not more effective than placebo. Meta-analyses of the results of three placebo-controlled trials (n = 130) favored Kava for GAD treatment with effect sizes between 0.59 and 0.99 (standard mean difference) without reaching statistical significance. Kava is an appealing treatment option to GAD patients who are more attune to natural remedies or lifestyle approaches to reduce stress. Positive patient experiences and improvement of vagal cardiac control due to Kava treatment were also reported in the literature. Kava is safe and well tolerated for short-term (4-8 weeks) therapeutic use at a dosage of 120-280 mg per day of Kavalactones, regardless of dosage schedule.
Conclusions: Current evidence, although promising, is insufficient to confirm the effect of Kava for GAD treatment beyond placebo. New evidence is expected from a large, multisite ongoing trial.
Keywords: Kava; generalized anxiety disorder; meta-analysis; phytomedicine; systematic review.