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 sheds light on how the use of different types of cannabis affects driving, feelings of intoxication and cognitive function.
The effects of cannabis on driving automobiles are nowhere near as predictable as those of alcohol, said Professor Iain McGregor, academic director of the Lambert Initiative for Cannabinoid Therapies.
Most street cannabis is high in THC, the chemical in cannabis that causes people to 'get high', but drugs are increasingly being used that also contain cannabidiol (CBD), a better known non-toxic cannabinoid. in the treatment of severe epilepsy but also useful in treating anxiety, psychosis and pain. It has often been argued that the administration of CBD may also reduce some of the deficiency caused by THC.
Cannabis and driving
It is important for people to understand the potential impairment of driving when 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 use medicinal cannabis, many of whom are told by their doctors not to drive under any circumstances,” said Professor McGregor.
"And although it is illegal to drive while impaired by medical cannabis, it is permitted to drive after taking opioids, benzodiazepines and low doses of alcohol, although it can be argued that they can cause even more impairment 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 double-blind, randomized, crossover study, 14 healthy volunteers with a history of light cannabis use attended three outpatient experimental testing sessions where sham driving and cognitive performance were assessed. patients.
High THC cannabis was vaporized at a dose (125 mg) that caused consumers to experience strong feelings of intoxication and reluctance to drive, according to the study.
In a test performed on a sophisticated driving simulator, those given THC were debuffed for four hours on a demanding car after a task in a complex city environment, although it was not a simpler standard road driving task. The study found that the type of impairment seen with high-THC cannabis resulted in greater pathway weaving.
However, on other measurements, the intoxicated participants were a bit safer, leaving a greater gap between them and the car in front of them and showing no tendency to speed.
CBD and impaired driving
Contrary to expectations, the study found that the addition of CBD did not reduce feelings of intoxication, nor did it decrease impaired driving compared to standard high THC cannabis. Under certain circumstances, the study found that the CBD exacerbated THC-induced deficiency.
Even high THC cannabis had only one effect
Modest harm to simulated driving performance. The only performance measure that deteriorated significantly with cannabis was lane interlacing, and participants in the high THC and balanced THC / CBD groups tended to leave a larger gap between themselves and the car in front. compared to the placebo group.
This study is the first in a series of research on cannabis and driving planned by the Lambert Initiative. A study assessing the accuracy and sensitivity of roadside drug testing procedures will be published shortly; an enlarged version of this study on actual driving on the road is currently underway in collaboration with the University of Maastricht (the Netherlands); as well as an upcoming trial assessing simulated driving and cognitive performance using CBD-only cannabis products.
"A better understanding of the effects of cannabis on driving is imperative so that legal frameworks can be updated and unambiguous advice can be given to patients, all based on high-quality scientific evidence," said the Professor McGregor.