Conference Presentations

2022 International Neuropsychological Society (INS) meeting

Dr Thomas Marcotte presented a talk on Cannabis, Driving Performance and Users’ Perception of Safety: A Double-Blind, Placebo-Controlled Randomized Clinical Trial of Smoked Cannabis.

With increasing legalization of cannabis for medicinal and recreational use, there are growing concerns regarding cannabis-impaired driving. There remains uncertainty regarding the magnitude and time course of cannabis effects on those most likely to be on the road – regular users smoking to a desired level of intoxication. The appropriate waiting period before driving after smoking is a significant public safety concern, with some suggesting 3-5 hours, and others recommending longer. Since this decision may be self-determined based upon “feeling impaired”, it is important to understand the accuracy of these self-evaluations. Lastly, while greater frequency of use is associated with increased behavioral tolerance, the relationship to driving remains poorly understood, since individuals may counteract tolerance by ingesting greater amounts to achieve desired psychoactive effects.

The aims of this study were to determine the magnitude and time course of driving impairment produced by cannabis with different THC percentages, concordance between perceived impairment and observed performance, and the effects of use history on driving performance.