Consumers who abstain from cannabis for 48 hours drive no differently than abstainers, according to driving simulator data published in the journal Psychopharmacology. Researchers with the University of California, San Diego, evaluated driving performance in a cohort of 191 cannabis consumers. Participants completed a 25-minute simulated drive following 48 hours of cannabis abstinence. A subset of near-daily consumers was matched against non-using controls.
“The current study showed no evidence of a dose-effect relationship between simulated driving performance following a brief abstinence period” investigators reported. “The current study also shows no evidence of short-term residual effects on simulated driving performance when comparing frequent cannabis users to a healthy non-using comparison group”.
Despite subjects’ lack of psychomotor impairment, researchers acknowledged that some participants tested positive for THC at levels that would classify them as ‘under the influence’ in jurisdictions with either zero-tolerant or per se THC blood limits. That’s because THC and its metabolites remain present in bodily fluids for extended periods of time following cannabis abstinence, whereas the acute effects of cannabis on psychomotor skills largely dissipate within a few hours.
12 September, 2025