Kava ineffective for Generalised Anxiety Disorder

8 December 2019

Findings published today in the Australian and New Zealand Journal of Psychiatry(opens in a new window) investigating the South Pacific plant medicine Kava for Generalised Anxiety Disorder (GAD) have shown no significant difference compared to placebo in anxiety reduction.

Led by Western Sydney University’s NICM Health Research Institute, the phase III clinical trial follows previous randomised controlled trials which demonstrated Kava (Piper methysticum) to reduce anxiety during short-term administration, and a call for the need for further research to be conducted into water-based formulations from the World Health Organization.

GAD is a chronic, debilitating psychiatric condition which can considerably impact a person’s occupational and social functioning. More treatment options are needed as pharmacotherapies are deemed to be moderately effective with many people not responding to treatment.

“The findings showed no significant difference in treatment response between the Kava group and the placebo group in anxiety reduction, and remission rates were also non-significant between the groups,” said Professor Jerome Sarris, chief investigator and NHMRC Clinical Research Fellow at NICM Health Research Institute.

The trial did not replicate previous study findings related to gene variation and showed no clear association between the GABA transporter gene and treatment response in the Kava group.

“We were unable to confirm that Kava could be used as a first-line treatment for Generalised Anxiety Disorder, however, based on previous evidence, standardised Kava still has support as a calmant for the short-term treatment of non-clinical anxiety such as ‘situational’ anxiety,” said Professor Sarris.

The safety evaluation showed no differences in adverse events between the groups and Kava was well tolerated with the exception of poorer memory and tremor and or shakiness.

An analysis of 171 participants was undertaken consisting of a multi-site 16-week double-blind, randomised, placebo-controlled study from 2015 to 2018 and investigating an aqueous extract of Kava dried roots administered twice per day in tablet form.

The primary aim of the study was to confirm anxiety symptom reduction and safety of Kava in a larger, longer term trial in people diagnosed with GAD, with secondary aims to confirm the relationship between specific genetic variations and response to Kava, and to explore the effects of Kava on the expression of specific genes.

The trial was funded by an NHMRC project grant (APP1063383), and co-funded by Integria Healthcare and involved researchers from The University of Melbourne, The University of Queensland, Swinburne University of Technology in Melbourne and University of Calgary, Canada.

The paper, Kava for generalised anxiety disorder: A 16-week double-blind, randomised, placebo-controlled study is available online:https://doi.org/10.1177/0004867419891246

This study was funded by an Australian National Health and Medical Research Council (NHMRC) grant (No. APP1063383) and co-funded by Integria Healthcare (who were completely uninvolved in the study design, data analysis as well as write-up and editing of the results). J.S. was supported by an NHMRC Clinical Research Fellowship (No. APP1125000). The raw material used in the investigational tablets was sourced specifically for the trial and is different from that used in products currently marketed by Integria Healthcare.