Kava for generalised anxiety disorder : a 16-week double-blind, randomised, placebo-controlled study

Jerome Sarris, Gerard J. Byrne, Chad A. Bousman, Lachlan Cribb, Karen M. Savage, Oliver Holmes, Jenifer Murphy, Patricia Macdonald, Anika Short, Sonia Nazareth, Emma Jennings, Stuart R. Thomas, Edward Ogden, Suneel Chamoli, Andrew Scholey, Con Stough

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Objective: Previous randomised, double-blind, placebo-controlled studies have shown that Kava (a South Pacific medicinal plant) reduced anxiety during short-term administration. The objective of this randomised, double-blind, placebo-controlled study was to perform a larger, longer-term trial assessing the efficacy and safety of Kava in the treatment of generalised anxiety disorder and to determine whether gamma-aminobutyric acid transporter (SLC6A1) single-nucleotide polymorphisms were moderators of response. Methods: The trial was a phase III, multi-site, two-arm, 16-week, randomised, double-blind, placebo-controlled study investigating an aqueous extract of dried Kava root administered twice per day in tablet form (standardised to 120 mg of kavalactones twice/day) in 171 currently non-medicated anxious participants with diagnosed generalised anxiety disorder. The trial took place in Australia. Results: An analysis of 171 participants revealed a non-significant difference in anxiety reduction between the Kava and placebo groups (a relative reduction favouring placebo of 1.37 points; p = 0.25). At the conclusion of the controlled phase, 17.4% of the Kava group were classified as remitted (Hamilton Anxiety Rating Scale score < 7) compared to 23.8% of the placebo group (p = 0.46). No SLC6A1 polymorphisms were associated with treatment response, while carriers of the rs2601126 T allele preferentially respond to placebo (p = 0.006). Kava was well tolerated aside from poorer memory (Kava = 36 vs placebo = 23; p = 0.044) and tremor/shakiness (Kava = 36 vs placebo = 23; p = 0.024) occurring more frequently in the Kava group. Liver function test abnormalities were significantly more frequent in the Kava group, although no participant met criteria for herb-induced hepatic injury. Conclusion: While research has generally supported Kava in non-clinical populations (potentially for more 'situational' anxiety as a short-term anxiolytic), this particular extract was not effective for diagnosed generalised anxiety disorder.
Original languageEnglish
Pages (from-to)288-297
Number of pages10
JournalAustralian and New Zealand Journal of Psychiatry
Volume54
Issue number3
DOIs
Publication statusPublished - 2020

Keywords

  • anxiety
  • depression_mental
  • kava plant
  • pharmacogenetics
  • therapeutic use

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