Marijuana use has been increasing across the United states since 2007. Previous research has found people who use both alcohol and marijuana may be at a higher risk for negative consequences when compared to those who use only one substance. The current study aims to address this issue and assess past-month alcohol use, marijuana use, and consequences for college students during their first three years of college.

The final sample for this study consisted of 997 students with a mean starting age of 18.1. Participants were surveyed four times each year for the three years the study took place. Measures included alcohol use, alcohol-related consequences, and marijuana use. Alcohol use was assessed using the Daily Drinking Questionnaire and cannabis use was assessed by asking participants how much they used it within the past month.  Consequences were assessed using the Young Adult Consequences Questionnaire which consists of 48-items in eight domains of alcohol related consequences. At baseline of the study, 19% of the sample reported using cannabis within the last 30 days and 64% reported past 30 day alcohol use. 

Analysis showed changes in alcohol consequences were not significantly associated with changes in cannabis use frequency along with cannabis use not predicting total alcohol consequences. Researchers found cannabis use frequency was associated with changes in risky behaviors, alcohol dependence, and self-care domains. Another finding was those students who had a higher average of cannabis use had greater endorsement of risky behaviors and blackout consequences. These findings show that students using both substances may be at a higher risk for specific consequences and targeted harm reduction interventions may help these students understand the additional risks.

Take Away: With an increase in marijuana use across the United States, there is concern for added risk in young adults using both marijuana and alcohol. The current study aims to address this issue and assess past-month alcohol use, marijuana use, and consequences for college students. 997 students were surveyed about alcohol use, marijuana use, and alcohol-related consequences four times each year for a three year study period. Analysis showed that changes in alcohol consequences were not significantly associated with changes in cannabis use frequency. Researchers found cannabis use frequency was associated with changes in risky behaviors, alcohol dependence, and self-care domains. These findings show that young adults using both substances may be at a higher risk for specific consequences with a potential need for targeted harm reduction interventions. 

Wardell, J. D., Egerton, G. A., & Read, J. P. (2020). Does Cannabis Use Predict More Severe Types of Alcohol Consequences? Longitudinal Associations in a 3‐Year Study of College Students. Alcoholism: Clinical and Experimental Research, 44(5), 1141-1150. doi:10.1111/acer.14320