College campus environments are often notorious for various kinds of substance misuse, with alcohol and cannabis use being at the forefront of this behavior set. Harmful drinking in college students continually leads to negative consequences in nearly every aspect of students’ lives, and cannabis is the most frequently consumed recreational drug among this population. As the prevalence of cannabis consumption increases across the United States and its universities, students may choose to use cannabis with alcohol simultaneously, or in a more specified order. The motivations and effects of concomitant use vary between persons, and very little research exists detailing the relationship between the two substances. The purpose of this study was to investigate the effects and potential consequences of substance use order with regards to alcohol and cannabis consumption.
The study’s sample consisted of undergraduate students from three different large universities in three states with differing laws concerning cannabis legality. A total of 258 students (N=258, 51.9% female) completed two bursts of surveys, each lasting a total of 28 days with five surveys per day. The students were eligible if they reported recent alcohol and cannabis co-use, in addition to reporting ability in order to participate in the battery of surveys. The two 28-day bursts were separated by three months and were longitudinal in design. The surveys contained information related to demographics, alcohol use patterns (AUDIT scores), cannabis use patterns (CUDIT scores), consequences for use of each substance (e.g., hangovers, driving while intoxicating, etc.), and a daily timeline feature where students would manually mark timeframes when they would use alcohol and cannabis, allowing for overlap and ordering to be presented. Analysis was conducted using generalized linear mixed modelling.
Results of the study found that on co-use days, cannabis was more frequently reported as the first substance consumed, mediating an overall reduction in the following alcohol consumption. The converse of this finding (alcohol first, lowering cannabis consumption) was not found to be true. An additional finding was if participants used greater amounts of cannabis or alcohol than is considered usual, greater amounts of the other substance would similarly be consumed, though still lower compared to independent use. A positive relationship between total alcohol consumption and consequences was found, but no significant relationship was found between cannabis and consequences, or different forms of co-use ordering and consequences.
Takeaway: the ordering of alcohol and cannabis consumption may be a predictor of total substance use on a co-use day. More research is needed to explore the motivations and effects behind concomitant alcohol and cannabis use.
Gunn RL, Sokolovsky A, Stevens AK, Metrik J, White H, Jackson K. Ordering in alcohol and cannabis co-use: Impact on daily consumption and consequences. Drug and Alcohol Dependence. 2021;218:108339. doi:10.1016/j.drugalcdep.2020.108339