Saccade and cognitive function in chronic kava users

Abstract

Kava is an extract from thePiper methysticumForst. f.plant that has been consumed in the Pacific islands for millennia and more recently, among indigenous populations, in northern Australia and throughout the Western world as an herbalmedicine. Through alterations onneuronal excitation, kava induces muscle relaxation, anasthesia, and has anxiolytic properties. There have been several isolated reports ofpsychotic syndromes, severe choreoathetosis and possible seizures following kava use. However, there is no conclusive evidence thatkava interferes with normalcognitive processes. We tested a group of current, ex, and nonkava users among an indigenous population innorthern Australia, using saccade and cognitive tests that have proven cross-culturalvalidity and are sensitive to subtle disruptions of thebrain arising from substance abuse or neuropsychiatric illness. Despite collecting data from among the heaviest reported kava drinkers inthe world, we found no impairment in cognitive or saccade function in individuals who were currently heavy kava users (and had been forup to 18 years), nor was there any impairment in individuals who had been heavy kava users in the past but had abstained for longer than6 months. Current and ex-kava users showed a higher rate of kava dermopathy, lower body mass index, lowered blood lymphocytesand, in addition, current kava users showed elevated liver enzymes. While there has recently been increasing concern about potentiallyfatalliver damage attributed to kava use, we have found no evidence of brain dysfunction in heavy and long-term kava users. © 2003 Nature Publishing Group.