UI researchers discover hyperlink between hashish and driving impairment

People who consume cannabis before driving have impaired driving skills and memory coding, researchers from the University of Iowa found.

UI scientists used driving simulations and EEG tests to analyze markers of impaired driving ability in marijuana users who use medical cannabis that is legal in Iowa.

Researchers from the National Institutes of Health, UI, and Advanced Brain Monitoring used cognitive tasks and a simulated driving test on their subjects to find brain signatures that correlate with impaired driving ability.

Timothy Brown, director of research into driving under drugs for the National Advanced Driving Simulator and co-author of the article, said the study was one of many his team looked at how drugs, especially over-the-counter and prescription drugs, act upon them Driving performance.

“We really focused on determining whether or not someone was impaired because of their brain activity,” Brown said.

The team conducted the research on the UI’s National Advanced Driving Simulator in Coralville.

The researchers applied an electroencephalogram – a cap with metal disks that detect brain waves – to each person’s scalp to study their brain responses. The study found that midline frontal theta power associated with focused cognitive control and memory coding decreased in subjects who inhaled marijuana prior to cognitive tests and driving tests.

“This area of ​​the brain is particularly affected by cannabis and is also reflected in the performance the vehicle operates on the road,” said Brown.

Chris Berka, CEO and co-founder of Advanced Brain Monitoring, said that other parts of the brain related to memory coding were not limited to just theta energy, while specifically suppressing cannabis consumption.

“It happens instantly, immediately after you inhale, and it takes five or six hours even after people report that they no longer feel intoxicated,” she said. “Theta is very important for memory. It’s important for complex cognitive tasks, but we still don’t fully understand why cannabis turns it off and how it does that. “

Berka, co-author of the paper and lead researcher on the project, said the researchers used cognitive tasks to test verbal memory, image recognition memory, and processing speed, all of which are related to driving performance.

The primary measure by which they recognize impaired performance is the standard deviation of the lane or the extent to which a driver is avoiding a lane.

“Then they drive for forty-five minutes in a simulated driving log, drive through some urban areas and then some long country roads and then we measure the mileage,” said Berka.

Gary Milavetz, Executive Associate Dean of the UI College of Pharmacy and co-author of the paper, prepared and analyzed the doses of cannabis plant material used in the study.

Milavetz said cannabis slows the speed at which a user drives, unlike alcohol, which does the opposite.

“That’s not necessarily a good thing as they can become a hazard by driving too slowly … and blocking traffic and making it a challenge for people to get around,” he said.

Cannabis users are slow to respond to street situations like changing traffic lights or moving pedestrians, Milavetz said.

“I think we need a better understanding of the amount of cannabis that caused the impairment, and by that I mean what gets into the bloodstream because that obviously goes into the brain and affects how people react to driving and most other activities and react. “” he said.

Milavetz said medical marijuana is used to treat anxiety, nausea, and vomiting caused by chemotherapy, among other things.

“People react differently to a dose of THC, some people appear to be severely impaired, some people appear to be moderately impaired, and some people have minimal impairment, but it’s still enough to be detectable in our research,” said Milavetz. “So I’m pretty confident that cannabis has an impairment, but it’s not necessarily a straight line relationship.”

Berka said she’s worked on many previous studies with the National Advanced Driving Simulator at the UI over the past decade to examine the effects of drugs and sleep deprivation on driving performance.

“Right now it is very difficult for road safety and the legal system to keep up with the pace of legalization, and there is a great unmet need to better understand how cannabis affects the brain, how different doses of cannabis affect the brain, and how does that lead to possible changes in performance, ”said Berka.

At the University of Colorado, Berka is involved in a new test in which subjects use their own legal cannabis, as opposed to the one issued by the National Institute on Drug Abuse for the UI study.

“These data are, in our opinion, one step closer to what we would call an in-the-wild study, which means that it is more representative of the way people use cannabis in the real world,” said she.