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ABSTRACT: Presently, little is known about a number issues concerning kava (Piper methysticum), including (i) whether kava has any withdrawal or addictive effects; (ii) if genetic polymorphisms of the cytochrome (CYP) P450 2D6 liver enzyme moderates any potential adverse effects; and (iii) if medicinal application of kava has any negative or beneficial effect on sexual function and experience. The study design was a 6-week, double-blind, randomized controlled trial (n = 75) involving chronic administration of kava (one tablet of kava twice per day; 120 mg of kavalactones per day, titrated in non-response to two tablets of kava twice per day; 240 mg of kavalactones) or placebo for participants with generalized anxiety disorder. Results showed no significant differences across groups for liver function tests, nor were there any significant adverse reactions that could be attributed to kava. No differences in withdrawal or addiction were found between groups. Interesting, kava significantly increased female's sexual drive compared to placebo (p = 0.040) on a sub-domain of the Arizona Sexual Experience Scale (ASEX), with no negative effects seen in males. Further, it was found that there was a highly significant correlation between ASEX reduction (improved sexual function and performance) and anxiety reduction in the whole sample. Copyright © 2013 John Wiley & Sons, Ltd.
Phytotherapy Research 01/2013; · 2.09 Impact Factor
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ABSTRACT: Overview: Increasing concerns over the potentially impairing effects of prescriptive sedative drugs such as benzodiazepines on driving have been raised. However, other alternatives such as natural medicines may also carry similar risks with respect to driving safety. Kava (Piper methysticum) is a psychotropic plant commonly used both recreationally and medicinally in the United States, Australia, and the South Pacific to elicit a physically tranquilizing effect. To date no controlled study has tested a medicinal dose of kava versus placebo and a standard sedative drug on driving ability and driving safety. Objective: Due to the need to establish the safety of kava in operating a motor vehicle, we compared the acute effects of the plant extract versus the benzodiazepine oxazepam and placebo using a driving simulator. Methods: A driving simulator (AusEd) was used by 22 adults aged between 18 and 65 years after being randomly administered an acute medicinal dose of kava (180 mg of kavalactones), oxazepam (30 mg), or placebo one week apart in a crossover design trial. Results: No impairing effects on driving outcomes were found after kava administration compared to placebo. Results on specific driving outcome domains revealed that the oxazepam condition had significantly slower braking reaction time compared to the placebo condition (p =.002) and the kava condition (p =.003). The kava condition had significantly fewer lapses of concentration compared to the oxazepam condition (p =.033). No significant differences were found between conditions for steering deviation, speed deviation, and number of crashes. Results were not modified by driving experience. On the Bond-Lader visual analogue sub-scale of alertness, a significant Treatment × Time interaction (p =.032) was found, with a significant reduction over time for oxazepam decreasing alertness (p <.001), whereas no significant reduction was found in the kava or placebo conditions. Conclusion: The results indicate that a medicinal dose of kava containing 180 mg of kavalactones does not impair driving ability, whereas 30 mg of oxazepam shows some impairment. Research assessing larger recreational doses of kava on driving ability should now be conducted.
Traffic injury prevention 01/2013; 14(1):13-7.
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ABSTRACT: Hypericum perforatum (St John's wort: SJW) has been extensively studied as an antidepressant in short-term trials, however little research has been conducted on longer-term efficacy.Our objective was to analyze the continuation data from a 26-week randomized, double-blind, controlled study of SJW (LI-160) vs. sertraline and placebo in major depressive disorder. 124 participant "responders" continued treatment after week 8, until week 26. They continued randomly assigned SJW (900-1 500 mg), sertraline (50-100 mg) or matching placebo.At week 26, on the primary outcome, Hamilton depression rating scale (HAM-D) completer scores were: SJW (6.6±4.5), sertraline (7.1±5.4) and placebo (5.7±5.4) with a significant effect for time (p=0.036). Comparisons between all treatments were however non-significant (p=0.61). This effect was mirrored on the other outcomes: the BDI, CGI-severity, CGI-improvement, and on intention-to-treat analyses.While the continuation data revealed an equivocal outcome between treatments at week 26, both SJW and sertraline were still therapeutically effective, with a pronounced "placebo-effect" impeding a significant result at week 26.
Pharmacopsychiatry 05/2012; · 2.07 Impact Factor
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ABSTRACT: Kava (Piper methysticum) is a psychotropic plant medicine with history of cultural and medicinal use. We conducted a study comparing the acute neurocognitive, anxiolytic, and thymoleptic effects of a medicinal dose of kava to a benzodiazepine and explored for the first time specific genetic polymorphisms, which may affect the psychotropic activity of phytomedicines or benzodiazepines.
Twenty-two moderately anxious adults aged between 18 and 65 years were randomized to receive an acute dose of kava (180 mg of kavalactones), oxazepam (30 mg), and placebo 1 week apart in a crossover design trial.
After exposure to cognitive tasks, a significant interaction was revealed between conditions on State-Trait Anxiety Inventory-State anxiety (p = 0.046, partial ŋ² = 0.14). In the oxazepam condition, there was a significant reduction in anxiety (p = 0.035), whereas there was no change in anxiety in the kava condition, and there was an increase in anxiety in the placebo condition. An increase in Bond-Lader "calmness" (p = 0.002) also occurred for the oxazepam condition. Kava was found to have no negative effect on cognition, whereas a reduction in alertness (p < 0.001) occurred in the oxazepam condition. Genetic analyses provide tentative evidence that noradrenaline (SLC6A2) transporter polymorphisms may have an effect on response to kava.
Acute "medicinal level" doses of this particular kava cultivar in naive users do not provide anxiolytic activity, although the phytomedicine also appears to have no negative effects on cognition.
Human Psychopharmacology Clinical and Experimental 02/2012; 27(3):262-9. · 2.48 Impact Factor
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ABSTRACT: Use of complementary medicines and therapies (CAM) and modification of lifestyle factors such as physical activity, exercise, and diet are being increasingly considered as potential therapeutic options for anxiety disorders. The objective of this metareview was to examine evidence across a broad range of CAM and lifestyle interventions in the treatment of anxiety disorders. In early 2012 we conducted a literature search of PubMed, Scopus, CINAHL, Web of Science, PsycInfo, and the Cochrane Library, for key studies, systematic reviews, and metaanalyses in the area. Our paper found that in respect to treatment of generalized anxiety or specific disorders, CAM evidence revealed current support for the herbal medicine Kava. One isolated study shows benefit for naturopathic medicine, whereas acupuncture, yoga, and Tai chi have tentative supportive evidence, which is hampered by overall poor methodology. The breadth of evidence does not support homeopathy for treating anxiety. Strong support exists for lifestyle modifications including adoption of moderate exercise and mindfulness meditation, whereas dietary improvement, avoidance of caffeine, alcohol, and nicotine offer encouraging preliminary data. In conclusion, certain lifestyle modifications and some CAMs may provide a beneficial role in the treatment of anxiety disorders.
Evidence-based Complementary and Alternative Medicine 01/2012; 2012:809653. · 4.77 Impact Factor
