Want to curb cannabis-related crashes? Don’t forget older adults, study finds
Among people over 50 who use cannabis, those most likely to drive after partaking are men, people who use daily, and those who use THC-containing products for mental health reasons
With cannabis-related vehicle crashes on the rise, a new study suggests that prevention campaigns shouldn’t focus just on young people.
That means they likely got on the road while the THC in cannabis still impaired their reaction times, attention and other abilities that are important to driving safely.
The findings, from a University of Michigan team led by addiction psychologist Erin E. Bonar, Ph.D., are published in the journal Drug and Alcohol Dependence. The data behind the study come from the National Poll on Healthy Aging, based at the U-M Institute for Healthcare Policy and Innovation.
Bonar and the poll team published an initial analysis in late 2024, but the new paper dives deeper into the data.
“So much of the effort to reduce ‘driving while high’ through awareness campaigns has focused on young people, but our findings show this is a cross-generational issue,” said Bonar, a professor of psychiatry at the U-M Medical School. “Targeting messages at those middle age and older adults with the highest risk of post-use driving could also include message about the options for addressing the health issues that they may be trying to self-treat with cannabis.”
Those most likely to drive after using cannabis
Adults age 50 and over who use cannabis products daily or nearly daily were three times as likely to say they had driven soon after using, compared with those who only use cannabis rarely, the study finds.
Those who use cannabis for mental health reasons were twice as likely to say they’d driven after using it, compared with those who didn’t list mental health among their reasons for choosing to use cannabis.
And men over 50 who use cannabis were 72% more likely to drive after using THC-containing products, compared with women in the same age group who use cannabis.
In all, the poll showed that 21% of people age 50 and up had used a cannabis product at least once in the last year, including 27% of those aged 50 to 64 and 17% of those aged 65 and up.
Of the 729 respondents over 50 who said they had used cannabis in the past year, 27% said they use it daily or almost daily, while 43% had used it only once or twice. The rest were divided between those who use monthly (14%) and weekly (16%).
Beyond the riskiest groups
While the study results suggest some groups of people over 50 who could especially benefit from targeted preventive messaging about the risks of driving after using cannabis, broad-based messaging appears to be needed, Bonar says.
In all, 65% of the people in the survey who said they use cannabis were between the ages of 50 and 64, with the rest over 65. But there was no difference between the age groups in likelihood of post-cannabis-use driving.
There were also no differences in post-use driving by age, race, ethnicity, income, history of loneliness, or caregiver status.
Those who live in states where recreational cannabis has been legalized were no more likely to drive after using the drug than those living in other states.
In addition to mental health, the poll asked about other reasons that adults over 50 might use cannabis, including several related to health. In all, 52% of people over 50 who use cannabis cited a mental health or mood-related motive for using cannabis, and 67% cited a sleep-related motive.
There was no difference in whether participants drove after cannabis use based on using it for pain, other medical reasons or sleep-related reasons, once the researchers adjusted the data. However, there was some signal that those who use it for sleep reasons may be more likely to drive after using.
This suggests a need to help adults age 50 and up understand that there are options for treating these conditions that have much more evidence behind them than cannabis, said Bonar. It also highlights the need for more robust research on which health conditions cannabis might address most effectively.
Age-specific messaging
Bonar and her coauthors also note that driving guidelines for people over age 50 who choose to use cannabis should also consider the effects of aging on cognitive and motor abilities, and the potential for interactions between cannabis and the prescription drugs that these adults are more likely to take.
Helping adults over 50 who choose to use cannabis understand the potential impacts of today’s more potent cannabis, compared with the forms available in their younger years, is also important, says Bonar.
And when advising people over 50 about reducing driving risks related to their cannabis use, she said, health care providers and public health agencies may want to focus on strategies like using cannabis at times when they’re unlikely to need to drive, such as before bedtime, and the importance of planning ahead for safe transportation via a designated driver or ride share service.
Bonar is a member of IHPI and of the U-M Addiction Center, the U-M Injury Prevention Center and the U-M Eisenberg Family Depression Center.
In addition to the new paper on cannabis use and driving among people over 50, the National Poll on Healthy Aging recently issued a report on driving behaviors among people age 65 and over. Find it at https://michmed.org/w4Ayn
Bonar and colleagues also recently published an Injury Prevention Center report on the impact of recreational cannabis legalization in Michigan, including data on motor vehicle crashes and fatalities linked to cannabis.
In addition to Bonar, the study’s authors are Lianlian Lei, Matthias Kirch, Kristen P. Hassett, Erica Solway, Dianne C. Singer, Sydney N. Strunk, J. Scott Roberts, Preeti N. Malani, and NPHA director Jeffrey T. Kullgren.
Citation: Driving after cannabis consumption among US adults ages 50 years and older: A short communication, Drug and Alcohol Dependence, DOI:10.1016/j.drugalcdep.2025.112985, https://authors.elsevier.com/a/1mCG51LiD3LPLZ
Journal
Drug and Alcohol Dependence
Method of Research
Survey
Subject of Research
People
Article Title
Driving after cannabis consumption among US adults ages 50 years and older: A short communication
Article Publication Date
10-Dec-2025
New computer simulation could light the way to safer cannabinoid-based pharmaceuticals
image:
Illinois researcher Diwaker Shukla shows how deep learning and large-scale computer simulations can help lead the search for safe synthetic cannabinoid-based pharmaceuticals. Photo by Fred Zwicky
view moreCredit: Photo by Fred Zwicky
CHAMPAIGN, Ill. — New psychoactive substances, originally developed as potential analgesics but abandoned due to adverse side effects, may still have pharmaceutical value if researchers could nail down the causes of those side effects. A new study from the University of Illinois Urbana-Champaign used deep learning and large-scale computer simulations to identify structural differences in synthetic cannabinoid molecules that cause them to bind to human brain receptors differently from classical cannabinoids.
“The largest class of NPS are often sold as the street drugs Fubinaca, Chimica and Pinaca,” said chemical and biomolecular engineering professor Diwakar Shukla. “In addition to the adverse side effects, the formulas used to produce NPS vary, making them challenging to detect in standard drug screenings.”
New psychoactive substances are synthetic compounds; one class mimics the effects of classical cannabinoids. However, the study found that NPS tend to activate distinct signaling pathways in the human brain compared to classical cannabinoids. Specifically, they often trigger what’s called the “beta arrestin pathway” rather than the “G protein pathway.” This switch in signaling can lead to more severe psychological effects.
The study’s findings are published in the journal eLife.
“New psychoactive substances bind very strongly to cannabinoid receptors in the brain and are slow to unbind, making them difficult to observe and simulate in standard laboratory or computer experiments,” Shukla said. “It can take a huge amount of computer time to see these rare binding and unbinding events.”
In the lab, graduate student Soumajit Dutta used a new simulation approach, the Transition-Based Reweighting Method, to estimate the thermodynamics and kinetics of slow molecular processes. The team found that TRAM can also be used to observe the rare, slow molecular processes involved in the unbinding of NPS from cannabinoid receptors — by efficiently sampling these events that would otherwise require massive computing resources.
The researchers also used the Folding@Home platform, which enables millions of volunteers worldwide to donate computing power. This approach allowed the team to run many simulations in parallel, stitching the results together and using algorithms to decide which simulations to run next. It allows for the study of very long or rare events that would be nearly impossible with a single computer or a small cluster.
Together, these methods allowed the researchers to uncover new physical insights into how NPS interact with receptors — insights that were previously out of reach due to computational limitations — pointing the way toward the design of safer cannabinoid-based drugs that could avoid harmful side effects.
By revealing the NPS signal via pathways associated with more adverse effects, researchers can now focus on designing new molecules that avoid triggering these pathways for medical use. Shukla said their findings could direct more researchers to aim for compounds that bind less tightly or unbind more readily, potentially reducing the drugs’ harm.
The National Institutes of Health award R35GM-142745 and the National Science Foundation supported this research. Shukla is also affiliated with chemistry, bioengineering, the National Center for Supercomputing Applications, the Center for Digital Agriculture and the Carl R. Woese Institute for Genomic Biology.
Editor’s note:
To reach Diwakar Shukla, email diwakar@illinois.edu. The paper “Characterization of binding kinetics and intracellular signaling of new psychoactive substances targeting cannabinoid receptor using transition-based reweighting method” is available online. DOI: 10.7554/eLife.98798.3
Bioengineering is part of The Grainger College of Engineering at Illinois.
Journal
eLife
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Title
New computer simulation could light the way to safer cannabinoid-based pharmaceuticals
