What’s New in Psychology?

The Risks of Simultaneous Use of Alcohol and Marijuana in Young Adults   

Jim Windell

           In 2019, according to the CDC, 37% of high school students in the U.S. reported lifetime use of marijuana with 22% reporting they used marijuana in the past 30 days.

           But the rate of marijuana use by young adults, ages 18 to 30, is even higher. Monitoring the Future found that marijuana use in the past year reported by young adults increased significantly in 2021 compared to five and 10 years ago.

           The National Institute on Drug Abuse indicates that alcohol remains the most used substance among young adults. In 2021, 66% of young adults reported alcohol use in the past 30 days, Binge drinking (having five or more drinks in a row) rebounded in 2021 from a historic low in 2020, during the early stages of COVID-19 pandemic. On the other hand, high-intensity drinking (having 10 or more drinks in a row in the past two weeks) has been steadily increasing over the past decade and in 2021 reached its highest level ever recorded since first measured in 2005.

           Perhaps of greater concern, the Monitoring the Future survey, an ongoing survey of the behaviors of adolescents and adults conducted at the Survey Research Center in the Institute for Social Research at the University of Michigan, estimates that 20 % to 25 % of high school seniors and young adults engaged in simultaneous alcohol and cannabis use within the past year

             Given that this behavior – the simultaneous use of alcohol and cannabis – is linked to a greater risk of adverse consequences, there is an urgent need to better understand the effects of simultaneous use and who is most vulnerable to adverse outcomes. This urgency is underscored by the legalization of cannabis use. Previous research has yielded mixed and limited results. A new study, recently published in Alcohol: Clinical & Experimental Research, sought to clarify the associations and consequences of simultaneous use in young adults.

           The researchers in this study collected data from 409 adults ages 18 to 25 (50% women, 48% White) in the greater Seattle area who reported recent simultaneous alcohol and marijuana use. Of importance, the sample included both college and non-college students. In six bursts over two years, young adults completed 14 days of online surveys, reporting their alcohol and marijuana use and related effects for the previous day.

           Participants reported drinking on 36% of survey days with a mean of 3½ drinks; on 28% of those days, they experienced at least one negative alcohol consequence. The subjects reported using marijuana on 36% of survey days with a mean of three hours high and at least one negative marijuana consequence on 56% of those days. Simultaneous alcohol and marijuana use was reported on 15% of survey days. On days of simultaneous use, participants consumed 37% more drinks and indicated 43% more negative alcohol consequences. Negative alcohol consequences included such things as doing something embarrassing and feeling clumsy or confused.

           Furthermore, on days of simultaneous use, participants reported being high for 10% more hours – without experiencing more negative consequences – compared to marijuana use days without simultaneous alcohol use. On days with marijuana use, each additional hour high was linked to 14% more negative marijuana consequences, and simultaneous use carried greater odds of feeling clumsy or dizzy.

           Although the researchers point out that the findings may not generalize to all populations, given the sample was higher-risk substance-using young adults, still the findings provide the strongest evidence to date that simultaneous use is high risk and should be the focus of ongoing education and prevention efforts. Such education and prevention efforts could include putting out messaging that those who use alcohol and marijuana simultaneously would particularly benefit from monitoring and limiting the amounts consumed.

           To read the original article, find it with this reference:

Fairlie, A., Calhoun, B., Graupensperger, S., Patrick, M. & Lee, C. (2023). Daily-level simultaneous alcohol and marijuana use and associations with alcohol use, marijuana use, and negative consequences in a young adult community sample. Alcohol: Clinical and Experimental Research, 47(9), 1690-1701.