PROJECT SUMMARY
Cannabidiol (CBD) is now a legal, widely consumed, substance in the United States, but research regarding
CBD’s effects in healthy populations remains sparse. Although findings of studies conducted in both healthy
and clinical populations suggest that CBD may produce sedative effects, conclusions have been hampered by
small sample sizes and other methodological limitations. Given that sedation and drowsiness could ultimately
impair driving performance and increase drivers’ risk of motor vehicle collision, understanding the effects of
non-prescription CBD on driving performance and cognitive function in non-clinical populations is paramount.
However, only 3 studies involving 83 adults worldwide, have investigated CBD’s effects on driving performance
and each have methodological limitations. To close this research gap, a 5-year project is proposed to further
our understanding of whether and how CBD may impact driving performance by dose and biological sex in a
sample of young healthy adults using a driving simulator and a battery of well-validated self-report instruments
and cognitive tests. Our long-term goal is to definitively determine the effects of CBD on driving performance
and motor vehicle collision risk among all drivers. The specific aims of this project are 1) determine the
effects of CBD on the driving performance of healthy adults aged 18-30 years by dose and biological sex, 2)
determine the effects of CBD on participants’ drowsiness, sedation, and cognitive function by dose and
biological sex, and 3) determine whether changes in participants’ drowsiness, sedation, and cognitive function
are associated with driving performance. The research strategy will involve a randomized, parallel-group,
double-blind, sex-stratified, three-arm trial. Three hundred participants will be randomized to receive either: (1)
300 mg of pure CBD oil (N=100), (2) 150 mg of CBD oil (N=100) or (3) placebo oil (N=100) matched in
appearance and taste. After baseline cognitive testing, treatment consumption, and a 120-minute wait period,
each individual will then participate in a 40-minute driving simulation and re-take the cognitive tests. Our
central hypothesis is that, relative to placebo, increasing doses of CBD will be associated with greater
impairment in driving performance, as well as increased drowsiness and sedation, and a decline in cognitive
function. We also anticipate greater impairment in these outcomes among males vs. females based on our
pilot study results. Given that CBD products are growing in popularity at an exponential rate, and their effects
in a healthy population are virtually unknown, the potential impact of this study is the collection of essential
data regarding the unintended consequences of CBD, which may be unknowingly endangering the public by
impairing drivers and increasing collision risk. This aligns with the National Institutes of Health’s mission which
is to, “foster fundamental creative discoveries, innovative research strategies, and their applications as a basis
for ultimately protecting and improving health.”