Smoking pot may impact one’s ability to drive for weeks after using, new research finds. Though marijuana is now legal for recreational use in two states, and for medicinal use in a number of states, little research has been conducted in to the effects of smoking and driving. But according to new findings, published in Clinical Chemistry, cannabis can be detected in the blood for weeks after the last use, at a level that might influence driving. In the study, the active ingredient in cannabis (THC) was detected in the blood of chronic pot smokers, even after 30 days of abstinence. “Our results demonstrate, for the first time as far as we are aware, that cannabinoids can be detected in blood of chronic daily cannabis smokers during a month of sustained abstinence,” the study authors write. “This is consistent with the time course of persisting neurocognitive impairment reported in recent studies.” Part of the problem is that with regular consumption, THC remains in the blood in variable concentrations that don’t necessarily decrease predictably the way alcohol does. “Acute impairment is well documented for hours after cannabis intake, whereas the persistence of chronic impairment is less clear,” the authors write. Marijuana is second to alcohol for driving and motor-vehicle accidents while impaired. However, drunk drivers are 10 times more likely to cause fatal car accidents than stoned drivers.
