Substance use among college students has increasingly emerged as a significant public health concern, particularly due to its comorbidity with mental health issues such as depression and anxiety. While previous studies have established links between single-substance use and mental health problems, there remains a lack of comprehensive research examining the relationship between dual or polysubstance use and mental health outcomes among diverse college student populations. To address this research gap, the current study aims to explore the relationship between alcohol, cannabis, and e-cigarette exclusive, dual, and polysubstance use and depression and anxiety among U.S. college students by racial and ethnic subgroup and stratified by sex.
The study utilized data from 83,467 undergraduate students (60,746 female and 22,721 male) who participated in the 2020–2021 Healthy Minds Survey, a web-based survey conducted across multiple U.S. campuses. The key independent variables were substance use patterns (exclusive use, dual use, and polysubstance use), while the mental health outcomes were depression (PHQ-9) and anxiety (GAD-7). To analyze the effects of substance use patterns on depression and anxiety, logistic regression models were employed, stratified by sex, and adjusted for sociodemographic factors, financial stress, social support, non-response weights, and clustering at the college level.
The study found a strong association between dual and polysubstance use and mental health issues among undergraduate students. Compared to students who used only alcohol, both male and female students who engaged in dual use of cannabis and e-cigarettes, as well as polysubstance use involving all three substances, exhibited higher odds of meeting the criteria for anxiety and depression. Female students demonstrated the highest risk for both anxiety and depression, while male students showed the greatest risk for depression. In contrast, students who abstained from substance use had significantly lower odds of experiencing anxiety and depression compared to any substance users. The study also identified differences in mental health outcomes by race and ethnicity, finding that African American students had lower odds of anxiety and depression compared to White students, while Middle Eastern/Arab American female students had higher odds of anxiety. These findings suggest that the relationship between substance use patterns and mental health issues is not solely determined by substance use but also varies according to the type of substances used, as well as race and gender.
Takeaway: Dual and polysubstance use, especially of cannabis and e-cigarettes, is linked to higher risks of anxiety and depression among U.S. college students, with differences by race, ethnicity, and sex.