One study may help determine how long you should abstain from cannabis before getting behind the wheel.
The study could help the province shape policy around cannabis use and driving or operating machinery. It’s being funded through a $35,000 competitive grant sponsored by the University of Alberta and the University of Calgary.
Dr. Scot Purdon, neuropsychologist with Alberta Hospital Edmonton, who is leading the study, said not enough is known about how long cannabis impacts the brain.
“Is it two days? Or might it take a week? That’s what we don’t know,” he said. “Healthy people will experience sensory changes and emotional changes and cognitive changes when they’re intoxicated with cannabis.”
It will examine how cannabis affects the user’s fine motor skills, attention span, ability to be distracted and verbal learning.
Two other researchers are involved in the study, Dr. Cameron Wild from the University of Alberta and Dr. Alexander Penney at MacEwan University. They’re also examining the relationship between impairment levels and the user’s age, duration and frequency of cannabis use.
Purdon originally thought the study would finish in the next six to nine months, but due to an overwhelming response from people interested in participating, he anticipates it will finish sooner.
“So many people have expressed interest,” he said. “A lot of people use cannabis or have used cannabis and have an interest in these results.”
The way it works
People wanting to participate will have to meet certain criteria. The study examines 120 young adults between the ages of 18 and 35 who describe themselves as heavy users.Participants can’t have any previously diagnosed mental health issues like depression or anxiety. If chosen, they’ll meet with a research coordinator for two to three hours.
“There are a number of parameters that we need to control before we can make strong inferences about this,” he said.
The participants will be asked if they’ve used cannabis in the last 24 hours, 30 days or a year. They’ll then undergo a series of cognitive tests, such as remembering words and drawings and using blocks to repeat patterns demonstrated by the coordinator.
The researchers will then look at the data and see what it reveals. Purdon said he’s keeping his mind open to the results, but hopes to see changes between duration between cannabis use and cognitive functioning.
To date the best information known about cannabis is that verbal impairments related to the drug can last for a week after use. Coordination problems also last for a while after consumption.
“That’s the best that we can say right now for scientific literature,” he said.
He adds that some studies suggest learning and memory could be affected for two weeks or longer.
Researchers are also looking to see if heavy users have built up a tolerance preventing THC, the active ingredient in cannabis, from impacting the brain’s cognitive functions.
He said results of the study could help provide guidance around cannabis use and driving a motor vehicle or operating heavy machinery.
While there is accurate testing of blood alcohol levels, like the breathalyser test, roadside testing for cannabis is currently under development.
The only way to test whether someone has consumed cannabis is through urine tests. Police detachments at a few cities across Canada are trying out a saliva drug test, which will detect THC in saliva.
Purdon said both only show the body metabolizing the drug, but they don’t actually reveal what’s happening in the brain.
“We’re still testing the metabolite of THC, not the actual psychoactive component.”
The study still needs 60 more participants. For those interested call 780-342-5294 for more information.
