Alcohol and cannabis continue to be the two of the most widely used substances on college campuses around the globe. Harmful drinking has the potential to negatively affect the health and safety of students and their communities, garnering the efforts of many institutions to provide recovery and intervention programs. Cannabis use has increased every year of late in many countries, and the long-term consequences of consumption have not been concretely defined. The combination of alcohol and cannabis may result in synergistic effects, leading to more intense forms of intoxication. This study aims to identify neuropsychological effects of combining alcohol and cannabis use in college students.
The study’s sample consists of 298 undergraduate students from the University of Caen Normandy who were enrolled in an ongoing project investigating young adult substance abuse. Participants completed questionnaires which measured the following characteristics: demographics, anxiety traits (via State-Trait Anxiety Inventory), depression traits (via Beck Depression Inventory), tobacco/nicotine dependence (via Fagerström Test for Nicotine Dependence), alcohol consumption (via Alcohol Use Disorders Identification Test), cannabis use (via Cannabis Abuse Screening Test), and neuropsychological performance (via Brief Evaluation of Alcohol-Related Neuropsychological Impairments). Participants were subcategorized as light drinkers (LD), binge drinkers (BD), or binge drinkers consuming cannabis (BDC). The data was analyzed using a series of covariations, linear mixed models, and k-means cluster analyses.
Results of the study found decreased neuropsychological performance measures in both the BD group and BDC group, relative to the LD group. Additionally, the BDC group had significantly lower measures for working memory, flexibility, and episodic memory sub-scores as compared to the BD group. Tobacco use and anxiety traits were also associated with neuropsychological detriments according to the cluster analysis.
Takeaway: while the effects of cognitive impairment via binge drinking have been well-established, this study provides a new layer to the existing literature concerning binge drinkers who also consume cannabis. This data suggests cannabis use may amplify cognitive performance deficits in heavy alcohol users, spurring the notion that interventions and treatment programs should provide the breadth of care necessary for co-users.