Perceived Social Acceptability of Driving While under the Influence of Cannabis and Alcohol May Sway Young Adult Behavior

Half of 18- to 25-year-olds believe that the average young adult drives or rides in a car at least once a month while the driver is under the influence of alcohol and cannabis. Yet, seventy percent believe that both driving and riding in a car while the driver is under the influence of both alcohol and cannabis is totally unacceptable, and three percent of young adults report driving under the simultaneous influence of alcohol and cannabis, according to a study just published in Alcohol: Clinical and Experimental Research. The findings indicate that perceptions of social norms may sway young adults’ behavior related to driving under the influence of alcohol and cannabis differently than they do for alcohol alone and may inform strategies to reduce driving under the influence of alcohol and cannabis.

The study analyzed data from a cohort of two thousand 18- to 25-year-olds in Washington State to understand the associations between perceived social norms and self-reported behaviors related to driving or riding in a car while the driver is under the influence of alcohol and cannabis.

The findings showed a statistically significant positive association between the perceived social acceptability of driving under the influence of both alcohol and cannabis, as well as of riding with a driver who is under the influence of both substances and the likelihood of engaging in that behavior oneself. Perceptions of how common it is for other people to ride in a car while the driver is under the influence of both cannabis and alcohol were positively associated with the likelihood of doing so oneself.

The researchers did not find a significant association between perceptions of how common it was for other young adults to drive under the influence of both cannabis and alcohol and the individual’s likelihood to do so. This finding was unexpected, as prior studies on alcohol have found perceptions of alcohol use by peers to be linked to one’s own alcohol use.

For the study, participants were asked whether, in the prior 30 days, they had driven within three hours of using alcohol or cannabis or ridden in a car with someone who had. Twelve percent said they drove after using cannabis, and 20 percent said they rode with someone who had used cannabis. With regard to alcohol, 12 percent said they drove under the influence, and 11 percent were passengers in a car with an alcohol-impaired driver. 

The rates of driving after using both alcohol and cannabis were lower–three percent for driving while impaired and five percent for riding with an impaired driver. However, simultaneous use of cannabis and alcohol seems to create greater impairment than either substance individually, with an estimated ten percent higher risk of accidents compared to driving under the influence of alcohol alone. Previous studies have found that many people perceive driving after cannabis use to be safer than driving after alcohol use.

The study highlights the discrepancy between perceived social norms and behavior and supports the need for efforts to reduce driving while impaired by the simultaneous use of alcohol and cannabis.

Young adult DUI behavior and perceived norms of driving under the influence of simultaneous alcohol and cannabis use. B. Hultgren, M. Delawalla, V. Szydlowski, K. Guttmannova, J. Cadigan, J. Kilmer, C. Lee, M. Larimer.

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