Substance use in university communities in the United States continues to threaten student safety and well-being, with cannabis and alcohol being two of the most used products. Young adults lead all age demographics in total cannabis use, with college students being no exception to the trend.  Alcohol use is an unfortunate commonality among many different college campuses, with the behavior being associated with numerous poor outcomes in student performance and well-being.  Cannabis and alcohol may often be used concurrently due to potential synergistic effects of the substances, leading to elevated experiences of intoxication.  When investigating human behavior, reinforcer pathology concepts study the interactions between reinforcement value and delay discounting.  This study uses a reinforcer pathologies approach to examine concurrent substance use in a college student population.   

The study’s sample is composed of 185 undergraduate students from a large Midwestern university who were grouped according to whether they endorsed alcohol use, alcohol + cannabis use (dual use), or neither.  Next, participants responded to questionnaires which assessed the following variables: substance-based delay discounting tasks, alcohol purchasing tasks, cannabis purchasing tasks, alcohol use (via Alcohol Use Disorder Identification Test), and cannabis use (via Cannabis Use Disorder Identification Test- Revised).  Data analysis was performed using principal components analyses with oblique rotations, exponential demand modelling, and hierarchical linear regression analyses.   

Results of the analysis found dual users to be at increased risk for developing an alcohol use disorder compared to those who use alcohol only.  Additionally, dual users were found to have much greater negative slope scores for delay-discounting measures when compared to the alcohol only group.  Lastly, exponential demand modelling found dual users to have the highest scores for alcohol demand across all study groups. 

Takeaway: concurrent use of alcohol and cannabis in college students may be associated with increased alcohol use disorder symptoms, in addition to high demand of the substance accompanied with steep delay discounting.  Interventions designed to treat substance abuse in university students may often need to accommodate for additional risks associated with dual use behaviors.

Naudé GP, Reed DD, Thornton TJ, Amlung M. Dual use of alcohol and cannabis among college students: A reinforcer pathologies approach. Experimental and Clinical Psychopharmacology. 20200413;29(4):407. doi:10.1037/pha0000369