The longitudinal association of cumulative depression with cannabis use disorder among young adults.

Objective: This study examined whether the cumulative experience of elevated depressive symptoms from age 19 to 23 was associated with cannabis use disorder (CUD) at age 26, and whether the association varied by perceived ease of access to cannabis and perceived risk for harms from cannabis use.

Method: Data were from 4407 young adults participating in the Community Youth Development Study. Cumulative experience of elevated depressive symptoms was calculated by summing the number of times a participant scored 10+ on the 9-item Patient Health Questionnaire across three biennial survey waves (age 19 to 23). To assess CUD, the Diagnostic Interview Schedule was used. Participants also self-reported their ease of access to cannabis and the perceived harm of regular cannabis use at the age 19, 21, and 23 waves. Marginal structural modeling was used to account for multiple time-varying and time-fixed covariates through use of inverse probability weights.

Results: In final weighted models, a greater number of time points (i.e., study waves) showing elevated depressive symptoms was associated with an increased likelihood of CUD at age 26 (Prevalence Ratio = 1.46; 95% CI: 1.20, 1.77). There was no strong evidence for moderation of this association by perceived ease of access or perceived risk for harms due to regular cannabis use.

Conclusions: Persistent experience of elevated depressive symptoms may place young adults at risk for cannabis use disorder. Strategies to reduce the burden of depressive symptoms among young adults may lead to downstream effects such as reducing the prevalence of cannabis-related problems.