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Concern about the long-term safety and addiction potential of synthetic psychopharmaceuticals has led to increasing scientific interest in botanical approaches to the treatment of anxiety. To investigate the anxiolytic (anti-anxiety) effects and tolerability of kava (Piper methysticum), a group of German researchers performed a double-blind, placebo-controlled clinical trial in 58 patients with "anxiety syndromes not caused by mental disorders." Patients were randomized to receive either placebo or 100 mg kava extract (standardized to 70 mg kavalactones) three times daily for 4 weeks. Treatment outcomes were evaluated through standard psychometric assessments, including the Hamilton Anxiety Scale (HAMA), HAMA subscales, a 60-item Adjectives Check List self-assessment scale, and the Clinical Global Impression scale (CGI). Assessments were made at baseline and at 7, 14, and 28 days.

After only one week of treatment, HAMA scores demonstrated a significant reduction in anxiety symptoms in patients taking kava as compared to placebo, and this improvement continued to increase throughout the course of the study. The differences between the HAMA scores of the two groups were statistically significant at all three assessment intervals (p<0.02). Similar statistically significant improvements were observed for the kava group in many categories of the other outcome measures, including :mental anxiety" and "somatic anxiety" as rated by the HAMA subscales, self-assessed "performance oriented activation" as measured by the Adjectives Check List, and "severity of disease" as rated by the CGI.

No adverse reactions were observed in the kava group during the course of the study. The investigators concluded that the positive risk/benefit profile demonstrated by the kava extract makes it "suitable for the general practitioner in treating states of anxiety, tension and excitedness." These findings support the results of previous kava studies.

[Lehmann, E., E. Kinzler, J. Friedemann. 1996. Efficacy of a special kava extract (Piper methysticum) in patients with states of anxiety, tension and excitedness of non-mental origin -- A double-blind placebo-controlled study of four weeks treatment. Phytomedicine 3: 113-119.] -- Evelyn Leigh, from HerbalGram 39.

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