Polysubstance use, defined as the consumption of more than one substance within a given period, tends to result in worse outcomes compared to the use of a single substance. This behavior is particularly prevalent among college students and is associated with a range of negative consequences, including substance use disorders and lower academic achievement. However, many previous studies rely on outdated data that do not reflect the current generation of college students, and there is a significant research gap, particularly in studies examining the simultaneous use of cannabis with substances other than alcohol and cigarettes. This study aims to fill these gaps by providing more up-to-date information on substance use patterns among cannabis-using college students and examining how these patterns are associated with cannabis-related and academic outcomes.
This study involved 309 undergraduate students aged 18-25 who had used cannabis at least three times in the past month. Data were collected through an online survey, which included demographics, frequency of cannabis use, use of other substances such as alcohol, cigarettes, various substances (e.g., cocaine, hallucinogens), and academic-related variables (e.g., GPA, the number of classes skipped). Participants were categorized into five groups based on their substance use patterns: (1) cannabis only (CO), (2) cannabis and alcohol (CA), (3) cannabis, alcohol, and cigarettes (CAC), (4) cannabis, alcohol, and other substances (CAS), and (5) cannabis, alcohol, cigarettes, and other substances (CACS). One-way ANCOVAs, controlling for age and sex, were conducted to examine group differences in cannabis-related outcomes, Cannabis Use Disorder (CUD) symptoms, and academic performance.
The study found that 95% of participants used both cannabis and alcohol, with about one-third also using additional substances. Only 5.3% used cannabis exclusively. Among the groups, those who used multiple substances, particularly the group using cannabis, alcohol, cigarettes, and other substances (CACS), reported the highest frequency of cannabis use, the most severe Cannabis Use Disorder (CUD) symptoms, and the worst academic outcomes, including the lowest GPA and most skipped classes. In contrast, cannabis-only users reported fewer negative consequences and CUD symptoms, indicating a potentially lower risk for adverse outcomes compared to polysubstance users. These findings highlight the importance of intervention programs for college students that address not only cannabis use but also the use of other substances, as polysubstance use is closely associated with more severe negative outcomes.
Takeaway: Polysubstance use among college students is linked to more severe cannabis-related issues and poorer academic outcomes, highlighting the need for interventions that address the use of multiple substances, not just cannabis alone.