Among 1,063 Australian medical cannabis users who drove in the past year, 28% reported driving under the influence, with inhaled THC-dominant products, illicit rather than prescribed use, and low perception of impairment being the strongest predictors.
Medical cannabis patients, prescribers, and road safety policymakers
28% reported driving under influence
What the researchers found
28% of driving respondents reported DUIC. 49-56% typically drove within 6 hours of medical cannabis use. Non-medical cannabis was perceived as more impairing than medical cannabis. Predictors of DUIC included inhaled administration, THC-dominant products, illicit rather than prescribed use, believing cannabis does not impair driving, and not being deterred by roadside testing.
Why it matters
As medical cannabis programs expand, understanding driving behavior among patients is critical. The finding that half of patients drove within 6 hours of use and that many do not perceive medical cannabis as impairing suggests a significant road safety gap.
The numbers in context
1,063 driving respondents; 28% (297) reported DUIC; 49-56% drove within 6 hours of use; non-medical cannabis perceived as more impairing than medical; 5 significant predictors identified via logistic regression
How the study worked
Cross-sectional survey subsection of the Cannabis as Medicine Survey 2020 (CAMS-20). 1,063 respondents who drove in the past 12 months answered driving-related questions about behaviors, attitudes, and perceptions. Binary logistic regression identified predictors of DUIC.
What this study cannot tell us
Self-reported driving behavior may underestimate actual DUIC rates. Cross-sectional design cannot establish causation. Sample drawn from an advocacy organization survey may not represent all medical cannabis users. Australian driving laws and testing may differ from other jurisdictions.
How to read the evidence
Large survey with regression analysis, but self-reported data from an advocacy-linked sample may not be representative
When this study was published
2023 study
The bigger picture
Medical cannabis patients face a unique challenge: they need their medication but may not recognize when they are impaired for driving. The finding that medical cannabis is perceived as less impairing than non-medical cannabis suggests patients may underestimate their impairment.
Questions still open
- Are medical cannabis users actually less impaired than non-medical users at equivalent doses? Would mandatory driving counseling for medical cannabis patients reduce DUIC? How long should patients wait after using medical cannabis before driving?
Common questions
Is it safe to drive after using medical cannabis?
Do medical cannabis users view their medication differently from recreational cannabis?
Read the original research
Driving-related behaviors, attitudes, and perceptions among Australian medical cannabis users: results from the CAMS 20 survey.
Journal of cannabis research, 5(1), 35
Citation
Arkell, Thomas R; Abelev, Sarah V; Mills, Llewellyn; Suraev, Anastasia; Arnold, Jonathon C; Lintzeris, Nicholas; McGregor, Iain S. (2023). Driving-related behaviors, attitudes, and perceptions among Australian medical cannabis users: results from the CAMS 20 survey.. Journal of cannabis research, 5(1), 35. https://doi.org/10.1186/s42238-023-00202-y