How do CBD and THC affect your driving? One is not like the other, study finds
After lots of pot vaping and over 200 hours of experimental drives, Australia researchers say operating a car after inhaling cannabidiol, or CBD — a non-intoxicating component of marijuana — does not impair one’s ability to safely hit the road.
That’s “great news” for the many people who have taken advantage of its medicinal properties to replace or supplement their over-the-counter or prescription medications, study lead author Thomas Arkell, a member of The Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney, said in a news release.
The researchers also found that moderate amounts of tetrahydrocannabinol (THC) — the psychoactive ingredient in marijuana that causes a “high” — alone, or combined with CBD, can produce “mild driving impairment” about 40 minutes after inhalation and for up to four hours.
After four hours, vapers were capable of driving with no apparent issues, according to the study published Tuesday in the journal JAMA.
“With cannabis laws changing globally, jurisdictions are grappling with the issue of cannabis-impaired driving,” Arkell said in the release. “These results provide much needed insights into the magnitude and duration of impairment caused by different types of cannabis and can help to guide road-safety policy.”
The team recruited 26 healthy “occasional users of cannabis” and had them vape four different types of marijuana, in random order and with no knowledge of what they were inhaling, over four separate days between May 2019 and March 2020.
The types of cannabis involved in the study contained mostly THC, mostly CBD, a THC and CBD combination, and a placebo with no active ingredients. Doses for both components were 13.75 mg, which for THC “was enough to cause strong feelings of intoxication,” the researchers said.
Each participant completed two, one-hour driving tests on a highway in “real-world conditions” alongside a driving instructor who could take control of the car if necessary.
The first drive began 40 minutes after vaping the cannabis and the second after four hours, according to the study. Each participant was measured on lane weaving, swerving and oversteering with a standard scientific test.
What do we know about CBD?
CBD from hemp, a type of cannabis plant, was legalized federally in December 2018, but the U.S. Food and Drug Administration has only approved one CBD prescription drug used to treat two rare, severe forms of epilepsy.
The agency says it’s “currently illegal to market CBD by adding it to a food or labeling it as a dietary supplement. The FDA has seen only limited data about CBD safety and these data point to real risks that need to be considered before taking CBD for any reason.”
Of the risks, the FDA says CBD can make you drowsy, give you gastrointestinal distress, induce liver injury and cause irritability.
Yet, a 2019 Gallup Poll found that one in seven Americans uses CBD products; 40% use it for pain, 20% for anxiety and 11% for sleep.
Studies have shown that CBD reacts with certain receptors in the central and peripheral nervous systems, although researchers don’t yet fully understand how, according to Healthline.
But experts are convinced CBD alters serotonin levels, also known as the happiness hormone. Low serotonin is associated with depression and anxiety.
