CBD Has Little Impact on Driving Even at High Doses

Cannabidiol (CBD) may not impair people’s cognitive abilities or driving abilities when taken in doses commonly used for medicinal purposes, a small Australian study suggests.

For the study, the scientists asked 17 healthy adults to complete a series of four driving assessments and cognitive tests after taking a placebo or CBD oil in doses of 15, 150, or 1,500 milligrams (mg). These doses represent amounts typically consumed to treat conditions such as epilepsy, pain, anxiety and sleep disorders, the researchers reported May 30 in the Journal of Psychopharmacology.

In each of these four test scenarios, participants completed tasks between 45 and 75 minutes after taking the placebo or dose of CBD oil, then again between 3.5 and 4 hours afterward. According to the researchers, CBD is believed to reach peak blood levels within three to four hours after an oral dose.

To demonstrate how CBD affects driving, participants had to drive behind another vehicle at a safe distance and then navigate simulated routes on urban freeways and rural roads. The scientists measured how well the participants controlled the car and how much the vehicle swerved or drifted. They also performed cognitive tests and took blood samples to determine the participants’ plasma concentrations of CBD.

None of the CBD oil doses appeared to impair driving or cognitive performance, or make participants feel intoxicated, the study found.

“Although CBD is generally considered ‘non-intoxicating,’ its effects on safety-sensitive tasks are still being studied,” said lead author Danielle McCartney, PhD, of the University of Sydney, in the university’s press release. “Our study is the first to confirm that CBD, when consumed alone, is driver-safe.”

Medical marijuana was legal in 37 US states and the District of Columbia as of February 2022, according to the National Conference of State Legislatures. While drunk driving is illegal in every state, laws against driving under the influence of marijuana and other drugs vary from state to state; You can view them on a website created by the Governors Highway Safety Association.

Driving under CBD is legal in Australia and many other countries, according to researchers. The results of the new study build on previous evidence suggesting that CBD does not necessarily cause intoxication. Another cannabis component, THC, can induce sedation and a euphoric high that has previously been associated with impaired cognition.

THC can negatively affect areas of the brain that control movement, balance, coordination, memory, and judgment, according to the US Centers for Disease Control and Prevention (CDC). For drivers, THC can also slow down reaction times and reduce decision-making ability.

While the new study suggests these issues may not occur in drivers using CBD oil, the study team warns that their findings only apply to the specific doses they tested. With higher doses of CBD or in combination with other substances, it is possible that riders will not function optimally.

“This study only looked at CBD in isolation,” said Dr. McCartney. “Drivers taking CBD along with other medications should do so with caution.”