As cannabis use becomes more prevalent across the United States, its combination with alcohol may also see an upward trend. Within college student populations, it is frequently reported that alcohol and cannabis are used together to produce concomitant effects, or to achieve unique effects specific to this duo. While the usage of either of these two substances can pose an array of negative consequences for students, the authors of this paper chose to investigate the negative consequences that occur for students who use alcohol and cannabis simultaneously (SAM users). Additionally, as these negative effects are delineated, the study sought to investigate whether these consequences differ between SAM users and concurrent users (CAM users, using both substances but not simultaneously) or single-substance users (using only alcohol or only cannabis). The 9 specific consequences of interest were: cognitive, blackout, vomiting, academic/occupational, social, self-care, physical dependence, risky behaviors, and driving under the influence. The study used participants from three large universities in the United States recruited via an email invitation and screened for eligibility based upon their use of cannabis and alcohol in the past year, as well as necessary verifiers for undergraduate enrollment (N=1390, 62.4% female, mean age= 19.8 yrs.). The participants completed a survey composed of questionnaires regarding their alcohol consumption in the past 3 months (Daily Drinking Questionnaire), cannabis consumption in the past 3 months, negative consequences experienced from alcohol and cannabis using a combination of two established questionnaires (Brief Young Adult Alcohol Consequence Questionnaire, Brief Marijuana Consequences Questionnaire) that were modified according to whether a student fell into the category of SAM, CAM, or a single-substance user. Analysis consisted of pairwise group comparisons and subsequent logistic regression modelling. Results of the study found a significantly greater number of negative consequences experienced by the SAM group as compared to the CAM and single-substance use groups. When comparing the CAM and single-substance user groups, only the consequence related to the number of blackouts was found to be different. Of particular sociological importance, the negative consequences driving under the influence and cognition (feeling mental fog, confusion, etc.) were also found to be significantly more prevalent in the SAM group as compared to the other groups. This could be attributed to the physiological effects (namely, increased THC bioavailability) in SAM users’ bloodstream.
Takeaway: Simultaneous use of alcohol and cannabis in college students results in a uniquely higher number of negative consequences as compared to using the substances separately. Intervention councils should seek methods to attenuate this specific behavior amongst college students to prevent life-threatening and cognition impairing events.