The impact of traditional kava (Piper methysticum) use on cognition: Implications for driver fitness

Abstract

Ethnopharmacological relevanceFew studies have examined the impact of kava (Piper methysticum G. Forst. f.) on cognition when consumed at traditionally influenced volumes; most have used modified tablet-form kava, with the results erroneously overlaid on naturalistic kava consumption. Kava is a culturally significant Pacific drink with similar effects to Benzodiazepine. Traditionally influenced kava use sessions last, on average, 6 h in which attendees consume 3.6 L (7.6 pints) each of beverage kava, with some then driving home. Aim of the studyThis study evaluated the impact of traditionally influenced kava consumption on participants' neurological functioning. Testing occurred before, throughout and immediately following a typical faikava (kava-drinking) session, with the data then used to assess kava's potential impacts on driver functionality and safety. MethodsKava using participants (n = 20) were assessed with the Brain Gauge following and during a traditionally influenced kava session and compared against control (n = 19). Brain Gauge measures slight changes to six cognitive faculties: Speed, Accuracy, Temporal Order Judgement (TOJ), Timing Perception, Plasticity, and Focus. Results and conclusionsComparisons of the within-cohort data showed a positive change in the Focus for the active group at the final testing point following 6-h of kava consumption. Between-cohort data showed a significant level of regression in the active participants' TOJ at the final testing point. No statistically significant level of impairment for the other five cognitive domains was detected. Although the results suggest that kava when consumed at traditional levels may have a slight positive effect on Focus, this result needs to be treated with caution, given the significant level of impairment noted at the final testing point for participants' TOJ. Temporal Order Judgement is associated with executive function, including decision making, behavioral control and information processing, all crucial aspects of driver safety. This is a new finding and suggests kava effects following traditional use differ from those caused by other substances commonly used for social or recreational purposes, such as cannabis, alcohol and other euphoric substances, and may impair driver safety, although again, in a different way to other commonly consumed recreational substances. The findings also add quantitative understanding to ethnographic data on kava effects, suggesting the often-used term ‘kava intoxication’ is misleading and incorrect.