An Australian study looks at the impact of strict driving laws in that country on medical cannabis patients; and their attitudes towards/prevalence of driving under the influence.
In most states in Australia, driving a vehicle while having any detectable level of THC in the bloodstream is illegal, regardless of lack of impairment and regardless of whether a patient has a medical cannabis prescription. The only state at this point to have a medical defense in place is Tasmania.
Australia’s laws, currently being challenged by various organisations and politicians, effectively acts as a driving ban as THC can be detected up to weeks after consumption; long after any impairment may have occurred.
Researchers from multiple Australian universities conducted a cross-sectional online survey of Australians using cannabis for a medical condition between December 2022 and April 2023, focusing on the issue of driving. As well as capturing demographic and clinical information, self-reported driving under the influence of cannabis (DUIC) was assessed along with driving-related behaviours, and views about impairment.
Of the 2,609 respondents who had driven in the past 12 months, 73% were using prescribed medical cannabis and 28.3 % reported driving under the influence of cannabis.
Among the factors associated with significantly increased odds of driving while under the influence were more frequent medical cannabis use, being male, using illicit and smoked cannabis, and believing that cannabis does not impair driving. 69.1% of those reporting DUIC believed they weren’t impaired; but as mentioned, impairment (or lack thereof) doesn’t change anything in terms of the application of driving laws.
When asked how long after taking medical cannabis did patients think they were safe to drive, 20.7% of oral users, 30.7% of smokers and 16% of vaporiser users said less than an hour.
In 2021, researchers at Australia’s Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney indicated a ‘window of impairment’ of between three and 10 hours based on moderate to high doses of THC – but that impairment was not a straightforward situation.
Of survey respondents in the latest study who had been roadside tested in the 12 months prior, 15.1 % tested positive and were subsequently convicted. However, the presence of roadside drug testing did deter many from driving after using medical cannabis, with just over half either deterred or it affecting the type of medical cannabis used.
Other findings:
- 80.0 % said they can accurately gauge their driving ability after using medical cannabis.
- 81.1% said the tended to drive more carefully.
- 58% reported tending to leave a larger gap between them and the car ahead.
- 55.8% felt they were more in control of the vehicle.
- 75.0 % disagreed or strongly disagreed that they are slower to react to sudden situations.
- 83.3% disagreed it was harder to remain focused.
- 88.0 % disagreed they found it harder to drive in a straight line.
- 95.7 % disagreed they were taking more risks.
Commenting on their findings, the study’s authors said while roadside drug testing is clearly a robust driving deterrent, it also acts as a barrier to patient access.
“As cannabis policies continue to evolve, and as patient access continue to expand, efforts to reduce DUIC need to account for the nuances of therapeutic use. Further research is needed to better understand how prescribed medical cannabis impacts driving and cognition.”
The study has been published in the journal Transportation Research Part F: Traffic Psychology and Behaviour.
