Can Smoking CBD Affect a Person’s Driving? Study authors who have published in JAMA have asked this question. Your 22 study participants smoked and all inhaled: cannabis with CBD, cannabis with CBD and THC, cannabis with THC alone, and placebo. Each participant then passed eight driving tests. The authors measured the drug’s effect by how badly the drivers got off track at different times.
One question before this story goes any further: does a sample size of only 22 healthy occasional marijuana smokers really provide useful data?
It turns out to be, and that’s because of the smart choices the researchers made in designing the study. We’ll come back to these points in a minute.
The researchers wanted to know if there was a difference in impairment between CBD use and THC use. THC is the intoxicating component of marijuana. CBD, or cannabidiol, is a chemical that belongs to a class of molecules called cannabinoids. In animal experiments it is assumed that cannabinoids weaken the effect of dopamine. THC does just the opposite.
In this study, the driving skills of the participants were tested at different times after inhaling the individual study drugs after 40 minutes to 240 minutes. The results showed a slight increase in track weaving in the THC and THC plus CBD groups. The difference was greatest, measured at the 40-minute and 100-minute mark.
The CBD-only group had the same amount of track weaving as the placebo group.
David L. Streiner, PhD, CPsych said the biggest difference was between the THC with CBD smokers and the placebo group – at 1.72 cm, just over half an inch. “It’s hard to imagine that this is a driving risk. The biggest differences are in perceived ability to drive, not actual ability, ”said Dr. Streiner, professor in the Department of Psychiatry and Behavioral Neuroscience at McMaster University and Professor in the Department of Psychiatry at the University of Toronto. He wasn’t part of the study.
The authors acknowledge that the doses tested may not be the same as those commonly used. CBD products are not regulated, so the amount of CBD and other components in products bought by the public may not match the amount on the label. The same goes for THC products that are not bought in cannabis pharmacies.
Could the study results reassure CBD users that their ability to drive would not be affected by using CBD products? Lead author Jan Ramaekers, PhD, Maastricht University, The Netherlands, said that while CBD products are unregulated and therefore the exact doses given to users of oral or inhaled CBD products are unknown, there is evidence that the Driving ability may not be affected.
The added risk is that there have been some inconsistencies in the labeling of CBD products. Some contained some THC when they shouldn’t. There has been a lot of discussion about whether this was a willful act or mere negligence.
It is clear that more research is needed. Only when CBD products are regulated due to the possible adulteration with THC and other ingredients not mentioned. This randomized, double-blind study, in which neither participants nor researchers knew which substance the participant was inhaling, was carried out at Maastricht University.
Back to the question of the size of the study
Dr. Streiner told Medical Daily that the researchers did two important things when determining how many subjects would be needed for the study. “They performed a sample size calculation based on previous research and used a cross-over design.” “It’s more powerful than design between subjects,” he explained, because it eliminates the differences between people.
According to the NIH, crossover attempts are different because each participant takes each test. Since each of the 22 subjects inhaled each of the study drugs and took part in all eight driving tests, the results are more meaningful than if one person had only taken one driving test. Test variations from one person to another will be reduced and the end results will theoretically be more accurate.
The study was funded by the Lambert Cannabinoid Therapeutics Initiative at the University of Sydney, Australia.
Yvonne Stolworthy MSN, RN graduated from Nursing School in 1984 and has passed many Years in critical care and as an educator in a variety of settings including clinical trials.