The association between depression, anxiety and substance use among Canadian post-secondary students

Purpose: This study aims to examine the association between depression, anxiety and substance use among Canadian post-secondary students. Methods: This study used data from the spring 2016, American College Health Association National College Health Assessment II (ACFIA-NCHA II) survey. It includes 43,780 college students from 41 Canadian post-secondary institutions. The exposure variables of interest were alcohol, cannabis and tobacco use, and the outcome variables of interest were diagnosis or treatment for depression and/or anxiety. Descriptive statistics, univariate and multivariate logistic regression models were used to analyze our data. Results: Our study found that 14.7% of post-secondary students were diagnosed or treated for depression and 18.4% for anxiety within the past 12 months. Among current (past 30 days) substance use, it was reported that alcohol (69.3%), cannabis (17.9%) and tobacco (11%) were the most common. There was a significant association between depression and current tobacco use (OR =1.36, 95% CI: 1.22-1.52, P<0.001) and current cannabis use (OR =1.17, 95% CI: 1.05-1.31, P<0.001). There was also a gender-specific association between anxiety and female alcohol users (OR =1.41, 95% CI: 1.24-1.62, P<0.001). Conclusion: The results of this study found significant associations between depression, tobacco use and cannabis use, and anxiety and alcohol use among post-secondary students. These conditions should be screened concurrently for improved outcomes among this vulnerable population.