A new study finds combined use of pot edibles and alcohol leads to greater and longer-lasting driving impairment, and the combo could be missed by sobriety checks.
A new study is raising questions about what roadside sobriety tests actually detect—and what they might miss.
Researchers at Johns Hopkins Medicine, with support from the National Institute on Drug Abuse, studied how marijuana edibles and alcohol affect driving performance.
During multiple experiments, 25 healthy adults, ages 21 to 55, were given pot-infused brownies, alcohol, both drugs, or placebos.
During each session, the participants were asked to complete simulated driving tasks and standard field sobriety tests.
The first major finding: Combining edibles with alcohol caused greater and longer-lasting driving impairment than either substance alone.
Increased impairment occurred even at alcohol levels below the legal limit of 0.08%.
Researchers say the interaction of these two drugs may be synergistic, meaning the combined effects can exceed the impact of each drug individually.
The second major finding: Cannabis edibles —either alone or combined with alcohol—did not significantly impair performance on standard field sobriety tests.
Participants were only identified as intoxicated at the highest alcohol dose tested.
The principal investigator says, “This is the first controlled study to examine how cannabis edibles and alcohol interact, despite their growing combined use.”
The authors say these findings highlight an urgent need for public education on the risks of combined drug use and for improved roadside impairment detection methods.
Source: JAMA Network Open
Author Affiliations: Johns Hopkins University School of Medicine, University of Maryland, Baltimore, University of California, San Diego
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