Kava anxiety depression spectrum.
(Care and treatment)
Depression, Mental (Research)
Kava plant (Usage)
Kava plant (Health aspects)
Materia medica, Vegetable (Usage)
Materia medica, Vegetable (Health aspects)
Plant extracts (Usage)
Plant extracts (Health aspects)
|Publication:||Name: Australian Journal of Medical Herbalism Publisher: National Herbalists Association of Australia Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 National Herbalists Association of Australia ISSN: 1033-8330|
|Issue:||Date: Fall, 2009 Source Volume: 21 Source Issue: 3|
|Topic:||Event Code: 310 Science & research|
|Geographic:||Geographic Scope: Australia Geographic Code: 8AUST Australia|
Sarris J, Kavanagh D, Byrne G, Bone K, Adams J, Deed G. 2009. The
Kava Anxiety Depression Spectrum Study: a randomized placebo controlled
crossover trial using an aqueous extract of Piper methysticum.
Piper methysticum (kava) has been embroiled in controversy over the last few years after concerns of heptotoxicity prompted its withdrawal or restriction in a number of countries including Australia. On closer inspection it appears that many of the reported cases of liver damage involved concomitant ingestion of other potentially hepatotoxic agents and/or the use of an extract including the arial parts of the plant (which contain the alkaloid pipermethysticine). Traditionally kava is given as an aqueous extract of the peeled root and a number of recent studies have been undertaken to determine the safety and efficacy of this type of preparation.
Among its numerous activities kava has demonstrated empirical efficacy as an anxiolytic. Anxiety disorders are not only increasingly common in our society and potentially quite disabling, but at present patients often have limited pharmaceutical treatment options. The most commonly used drugs, benzodiazepines, are addictive, not recommended long term and have a number of substantial side effects. Thus there is a need for alternative treatment options such as the use of kava.
Researchers in Queensland recently completed the Kava Anxiety Depression Spectrum Study (KADSS) assessing the efficacy and preliminary safety of kava in treating anxiety, the effect of kava on co-occurring depressive mood and whether levels of depression at baseline predicted anxiolytic response to kava.
The trial was a placebo controlled double blind crossover design conducted over three weeks. Participants were adults each of whom had experienced at least one month of persistent worry or anxiety (scoring >10 on the Beck Anxiety Inventory). None of them had taken conventional pharmaceuticals for anxiety or depression within the last month. The first week of the study was a placebo run in and then for the subsequent weeks the patients received either placebo or tablets of an aqueous extract of kava (3.2 g standardised to 50 mg of kavalactones).
At the end of week two the groups were swapped over so that each had an active treatment week and a week on placebo. Tablets were administered three times daily, two in the morning, two in the afternoon and one in the evening. The run in phase was an important design strength as patients with general anxiety are known for having significantly elevated responses to placebo. This allowed researchers to eliminate clear 'responders' from the study. Patients were assessed at baseline and after each week of the trial using the Hamilton Anxiety Scale (HAMA), the Montgomery-Asberg Depression Rating scale (MADRS) and the Beck Depression Inventory (BDI-II). After active treatment, scores on the HAMA dropped significantly (an average of -9.9 points) below baseline. There was a reduction of 11.4 points over placebo. Relative levels of depression did not predict the degree of anxiolytic response to kava when measured by any of the variables. However it seems the kava itself had an antidepressant effect when measured on the MADRS, but this was not significant (p = 0.003).
Kava also proved safe when taken at these levels as no serious side effects occurred and only minor adverse effects were noted (including nausea and dizziness). There were no clinical signs of hepatotoxicity noted during the trial. Overall, 250 mg of kavalactones exerted pronounced anxiolytic activity comparable (if not superior) to benzodiazepines and also showed a substantial antidepressant effect. However the study was only for a short period of time which limits the conclusions that can be drawn about long term efficacy and safety. There was a lack of a wash out period between phases resulting in some carry over effects. Further well designed studies are required to assess the safety profile and efficacy of kava in treating anxiety and depression.
Tessa Finney-Brown MNHAA
|Gale Copyright:||Copyright 2009 Gale, Cengage Learning. All rights reserved.|