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.

In a randomized, placebo-controlled double-blind study two groups of 29 patients each with anxiety syndromes not caused by mental disorders were treated for four weeks with three daily doses of 100 mg of Kava extract WS 1490 (Laitan®) from Piper methysticum rhizoma or a placebo preparation. Therapeutic efficacy was assessed by the Hamilton Anxiety Scale (main outcome variable), the Adjectives Check List and the Clinical Global Impression Scale (secondary target variables) after 1, 2, and 4 weeks of treatment. The HAMA overall score of anxiety symptomatology revealed a significant reduction in the drug group compared with the placebo group after one week of treatment. The difference between the two groups of patients increased during the course of the study. The results of the secondary target variables were in agreement with the HAMA score and demonstrated the efficacy of WS 1490 in patients with anxiety disorders. No adverse reactions caused by the medication were noted during the four weeks WS 1490 was administered.