Can patients who consume medicinal cannabis drive safely?
As cannabis for medical use becomes more readily available, it is imperative that the risks of driving be clarified through extensive research.
New research conducted by the Lambert Initiative for Cannabinoid Therapeutics from the University of Sydney highlights how the use of different types of cannabis affects driving, feelings of intoxication and cognitive function.
The effects of cannabis on driving are not nearly as predictable as those of alcohol, "said Professor Iain McGregor, academic director of the Lambert Initiative for Cannabinoid Therapies.
Most street cannabis is rich in THC, the cannabis chemical that causes people to get smashed, but more and more drugs are being used that also contain cannabidiol (CBD), a better known nontoxic cannabinoid. in the treatment of severe epilepsy but also useful for treating anxiety, psychosis and pain. It has often been suggested that administration of CBD may also reduce some of the THC deficiency.
Cannabis and driving
It is important for people to understand the potential impairment of driving while using cannabis, said Professor McGregor.
"There is no reason to believe that drug-impaired driving is safe and that it is important for people to understand the potential risks," said Professor McGregor.
"But this is a burning issue for patients who consume medicinal cannabis and many of whom are told by their doctors not to drive under any circumstances," said Professor McGregor.
"And while it is illegal to drive under the influence of medical marijuana, driving after taking opioids, benzodiazepines and low doses of alcohol can be can cause impairments even more than cannabis. It is clear that much more research is needed to fully understand the impacts. "
"Our research on medical cannabis and driving contributes to the ongoing political debate on issues such as safety, impairment and detection," said Professor McGregor.
The study, published in the journal Psychopharmacology, compared the effects of standard high-THC cannabis, balanced THC / CBD cannabis and cannabis placebo on simulated driving and cognitive performance.
In a randomized, double-blind, cross-over study, 14 healthy volunteers with a history of light cannabis use attended three outpatient clinical trial sessions in which simulated driving and cognitive performance were evaluated. patients.
High-THC cannabis was sprayed at a dose (125 mg) that caused high levels of consumer toxicity and reluctance to drive, according to the study.
In a test conducted on a sophisticated driving simulator, people who received THC were weakened for four hours on a demanding car after a task in a complex urban environment, although this was not a problem. simpler standard road driving task. The study found that the type of impairment observed with cannabis with a high THC content resulted in increased lane weaving.
However, on other measures, drunk participants were a little safer, leaving a bigger gap between them and the car that precedes them and showing no tendency to speed.
CBD and impaired driving
Contrary to predictions, the study found that the addition of CBD did not reduce feelings of intoxication nor did it decrease impaired driving compared to high-standard THC cannabis. In certain circumstances, the study revealed that the CBD exacerbated THC-induced deficiency.
Even cannabis with a high THC content had only one effect
Modest deleterious on simulated driving performance. The only measure of performance that significantly deteriorated with cannabis was track interleaving, and participants in the high THC and balanced THC / CBD groups tended to leave a greater gap between them and the car in front of them. compared to the placebo group.
This study is the first in a series of research on cannabis and driving provided by the Lambert Initiative. A study assessing the accuracy and sensitivity of drug testing procedures on the road will be published shortly; an expanded version of this study on actual road driving is currently being done in collaboration with the University of Maastricht (Netherlands); and an upcoming trial evaluating simulated behavior and cognitive performance using CBD-only cannabis products.
"It is imperative to better understand the effects of cannabis on driving so that legal frameworks can be updated and that unambiguous advice can be given to patients, all based on high-quality scientific evidence," said the director. Professor McGregor.