How stoned is too stoned to drive? That’s a question that the University of California, San Diego’s Center for Medicinal Cannabis Research is studying in lab tests where participants are instructed to, yes, inhale and drive — but on simulators.
Participants ages 21 to 55 commit about a day-and-a-half to the testing. Researchers obtain the legal cannabis in bulk from The University of Mississippi, which has a federal contract with the National Institute on Drug Abuse (NIDA) to cultivate cannabis for research purposes.
“We have a nurse roll joints for the study,” said Tom Marcotte, Ph.D., a neuropsychologist leading the study.
Participants in the double-blind study are divided up in groups who receive various dosages: a placebo, 5.9 percent THC, or 13.4 percent THC. Post-smoking session, participants conduct driving simulations and a drug recognition expert administers several field sobriety tests. The simulations test participants in various areas of driving, including how they respond to dividing their attention in performing a task: Do they take their eyes off the roadway? Do they swerve?
“Some of the more common tasks a driver might encounter,” said Marcotte of the simulations.
Study subjects also are also tested with an iPad app to see whether it can help give more information during field sobriety tests. And throughout the day, participants’ blood, saliva and breath are tested.
Marcotte and his researchers are more than halfway through the study, which will have 180 participants by the time it’s anticipated to end in the spring of 2019.
While this study focuses on smoking marijuana, Marcotte hopes to pursue future studies addressing other areas of cannabis use, including edibles and the combined effects of alcohol and cannabis.