A new study warns that driving after eating cannabis edibles can significantly impair road performance and reaction times, even if blood tests show THC levels far below the legal limit.The findings, published in JAMA Network Open, highlight a potential challenge for impaired-driving enforcement in Canada and some U.S.jurisdictions.Most previous cannabis-driving studies have involved smoked or inhaled marijuana, which more rapidly spikes levels of THC (tetrahydrocannabinol, the main psychoactive compound in cannabis) in the bloodstream.AMERICA HITS MAJOR MARIJUANA MILESTONE AS DAILY WEED USE SURPASSES DAILY DRINKINGEdibles are absorbed more slowly and can produce driving impairment even when blood THC concentrations remain relatively low.Researchers found that drivers who consumed higher doses of edible THC struggled with lane control, had slower reaction times and experienced greater speed fluctuations.
Yet, their blood tests stayed below the standard legal cutoff used to prove impairment at roadside traffic stops.Researchers measured how well drivers stayed in their lane, how quickly they reacted to road events and how consistently they maintained their speed.(iStock)To assess how oral cannabis impacts driving, researchers at the Centre for Addiction and Mental Health in Toronto conducted a trial with 40 healthy adult volunteers who regularly use cannabis.Each participant attended four separate sessions where they consumed soft-chew gummies containing either 0, 2, 10 or 20 milligrams of THC.CANNABIS COMPOUNDS COULD REVERSE DISEASE AFFECTING ONE-THIRD OF ADULTSThe researchers then tested the drivers using a driving simulator at two, five and 24 hours after consumption, tracking how well drivers stayed in their lane, how quickly they reacted to road events and how consistently they maintained their speed.Blood samples and self-reported ratings of intoxication were also collected.Participants recognized their own limitations, reporting a lower willingness to drive a...