TEMPORAL TRENDS IN THE ASSOCIATION BETWEEN CANNABIS USE AND MENTAL HEALTH IN A NATIONALLY REPRESENTATIVE SAMPLE OF CANADIAN YOUNG AND OLDER ADULTS

Abstract

Background With the impending legalization of recreational cannabis in Canada, it is important to examine the strength of association between cannabis use and common mental health concerns including depression, anxiety, and suicide and the extent to which these associations have changed over time. It is also important to examine the moderating effects of developmental age and biological sex on these associations. Methods This study uses Statistics Canada data from the 2002 and 2012 Canadian Community Health Survey’s Mental Health Component (CCHS-MH) which represent repeated cross-sectional surveys from nationally representative samples of Canadians 15 years of age and older (2002 n=36,984; 2012 n=25,113). Stepwise multivariate analyses were performed using linear regression for psychological distress and binary logistic regression for Major Depressive Episode (MDE) and suicidal thoughts and attempts. Time was accounted for as a binary indicator (2002 vs. 2012) and an interaction term between cannabis use and time was added to all the models. Additional interaction terms were added to the models to test the moderating effects of cannabis frequency, developmental age, and biological sex. Sensitivity analyses were performed to adjust for other substance use and socioeconomic covariates. Weighting and bootstrapping was utilized to present results reflective of the Canadian population. Results Cannabis use was positively associated with emotional problems, and this association strengthened over time, particularly for depression and suicidal thoughts and attempts. These temporal associations were similar across age groups and for males and females, and remained after controlling for other substance use and socioeconomic status. Conclusions Findings provide a baseline assessment of the Canadian population prior to legalization and direction for health promotion and prevention campaigns. Results highlight the need for awareness and regular monitoring of the cooccurrence of cannabis use and emotional problems and offer guidance for future research.