EEG‐Brain mapping, psychometric and psychophysiological studies on central effects of kavain ‐ a kava plant derivative

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Abstract
In a double‐blind, placebo‐controlled study the encephalotropic and psychotropic effects of kavain‐a synthetic kava plant derivative as compared with clobazam were investigated, utilizing EEG brain mapping, psychometric and psychopysiological analyses. 15 normal volunteers received randomized in weekly intervals single oral doses of placebo, 200 mg, 400 mg and 600 mg kavain as well as 30 mg clobazam as reference compound. EEG recordings, psychometric tests, evaluations of pulse, blood pressure and side effects were carried out at the hours 0, 1, 2, 4, 6 and 8. Brain maps of drug induced pharmaco‐EEG changes (pharmaco‐EEG maps) demonstrated that kavain exerted a significant action on the human brain function as compared with placebo characterized by a dose‐dependent increase of delta, theta and alpha 1 activity while alpha 2, beta activity and the centroid of the total activity decreased. These findings are indicative of a sedative effect which was, however, in type quite different from that of the 1·5 benzodiazepine. The latter produced a decrease of delta, theta, alpha 1 and alpha 2 and an increase of beta activity while the total centroid was accelerated. Interestingly, 200 mg kavain induced with a decrease of delta and beta activity and an increase of alpha activity and of total power also vigilance promoting effects. Psychometric investigations demonstrated also clear differences between the two compounds at the behavioural level. Kavain improved the noopsyche as compared with placebo in all 3 doses as there was a significant improvement in intellectual performance (Pauli test), attention, concentration, reaction time and motor speed (rigidity test), while opposite findings were observed after 30 mg clobazam. In regard to thymopsychic variables such as drive, wakefulness, affectivity, mood, well‐being, 200 mg kavain produced an improvement as compared with placebo while 600 mg kavain produced sedation as did 30 mg clobazam. Psychophysiological evaluations resulted in only minimal findings. Time efficacy calculations demonstrated after kavain a pharmacodynamic peak in the 1st to the 2nd hour then a drop and a second peak in the 8th hour while clobazam produced maximal central effects in the 1st hour which declined thereafter to show a second peak in the 6th hour. Topographically, most encephalotropic effects were found after kavain in the frontal, after clobazam in the central and parietal areas. Evaluations of pulse, blood pressure and side effect demonstrated good tolerability of both compounds with 30 mg clobazam producing more sedation than kavain.