What happened when researchers tested the impact of THC plus CBD on driving

THC—the intoxicating component of marijuana—impairs driving. Does CBD (the non-intoxicating component) counteract THC’s psychoactive effects, as some claim?

Scientists had 26 young adults vape (inhale) THC, CBD, THC + CBD, or a placebo on different days. Each dose of THC or CBD was 13.75 milligrams. After 40 to 100 minutes, and again after four to five hours, the volunteers drove for an hour at 60 mph. (Relax. The car had a second set of pedals for the research team.)

Compared to the placebo, lane weaving, swerving, and overcorrection during the first drive were worse after both the THC and the THC + CBD, but not after just the CBD. No differences were seen after four or five hours.

What to do

Don’t expect CBD to make THC safe for driving. And the THC in edibles—like gummies or brownies—takes longer to wear off than inhaled THC, because it takes longer to reach the bloodstream.

Photo: LIGHTFIELD STUDIOS/stock.adobe.com.