Many Medical Cannabis Users Report Driving While “Very High”

More than half of medical cannabis users report driving under the influence of cannabis shortly after use, and 1 in 5 say they had driven while “very high” within the previous 6 months, according to new research from Michigan Medicine.1


Of 790 survey respondents in Michigan who had sought medical cannabis recertification or new certification for chronic pain in 2014 and 2015, approximately 56% said they had driven within 2 hours of cannabis use.

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Moreover, 51% and 21% of users reported driving while a “little high” and “very high,” survey data showed.


Experts are warning against this practice as the legalization of cannabis continues to sweep across the country. According to lead study author Erin E. Bonar, PhD, driving after cannabis use may negatively affect users’ reaction time and coordination while on the road.


“There is a low perceived risk about driving after using marijuana, but we want people to know that they should ideally wait several hours to operate a vehicle after using cannabis, regardless of whether it is for medical use or not,” said Dr Bonar, who is an assistant professor of psychiatry and a practicing clinical psychologist at the U-M Addiction Treatment Services. “The safest strategy is to not drive at all on the day you used marijuana.”2


Findings also indicated that using greater amounts of cannabis and binge drinking were associated with driving while under the influence of cannabis, whereas individuals reporting higher levels of pain were less likely to drive while high.


Now, Dr Bonar and colleagues are calling for clearer guidelines about dosing and side effects, as well as an improved understanding of how factors including sex and body weight interact.


“We believe more research is needed to inform a larger public education effort that will help individuals understand the risks for themselves, and others, of driving while under the influence of cannabis,” she said in a press release.2


“It is especially needed during this time of rapid policy change as many states are determining how to manage marijuana legalization,” she added.2


—Christina Vogt




1. Bonar EE, Cranford JA, Arterberry BJ, et al. Driving under the influence of cannabis among medical cannabis patients with chronic pain [Published online January 9, 2019]. Drug Alcohol Dependence.


2. Medical cannabis users operating vehicles: New study reveals worrisome statistics [press release]. Ann Arbor, MI. Michigan Medicine. January 9, 2019. Accessed on January 10, 2019.