LAUSR

BACKGROUND Cannabis use and major depressive disorder (MDD) are common and often co-morbid in adolescents, but the nature and directionality of the relationship between these two conditions remains obscure. METHODS We examined results from the National Survey on Drug Use and Health. Weighted demographics were compared between adolescents with a history of cannabis use (N = 14,873) and never users (N = 73,079). Weighted logistic regression controlling for demographic variables and other substance use was used to determine the relationship between cannabis use frequency and MDD. RESULTS Adolescents with any history of cannabis use had significantly higher rates of lifetime and past year MDD, MDD with severe role impairment, and past year suicide attempt (p < 0.001). Comparing use frequency groups in the adjusted model revealed that heavy users (weekly or greater use) had significantly lower predicted prevalence of lifetime and past year MDD, and past year MDD with severe role impairment compared to light users and those who used cannabis >1 year ago. Rates of reported past year suicide attempt did not differ significantly by cannabis use frequency. CONCLUSIONS Adolescents with any cannabis use history have significantly higher rates of MDD. However, the directionality between frequency of use and MDD is counter to what was expected.