Originally posted on Kava Science Forum Novermber 2017.
Dr. S. Aporosa at the University of Waikato, New Zealand has studied the effect of kava drinking, at traditional levels, on cognitive tests related to driving ability.
Here is his recent poster on the topic.
Aporosa, S. “Understanding cognitive functions related to driving following kava (Piper methysticum) use at traditional consumption volumes.” British Association for Psychopharmacology Conference. No. 31 (8). SAGE Publications, 2017.
• As the six-hour tests session progressed, subtle changes were observed in many of the kava drinker’s, namely psychomotor slowing, a somnolent-like state, altered word pronunciation and a slowing of speech rate.
• The test results were not statistically significant for either reaction time or divided attention measures. To give some context to the reaction time difference found in this study with kava (active 22.10msec slower than mean after 6 hours), consuming 50mg of alcohol (equivalent to the current 0.05 NZ driver blood alcohol limit) slowed driver reaction time by 70msec, which increased to 120msec at 0.08 (the previous limit).
• Discordant to hypothesis, the findings show no correlation between consuming kava at traditional volumes and response latency or impairment on divided attention tasks.
• It is possible the measures selected for this study lacked sensitivity in detecting kava’s effect
He didn’t find statistically significant changes in Reaction Time of Divided Attention, but did note some qualitative behavioral changes which would indicate that people should still avoid driving if they have drunk too much kava. It is important to note that they didn’t actually test driving directly, but used something kind of like a video game setup to test reaction time, etc., as described here: