Cannabis abuse as a risk factor for depressive symptoms

Objective: This study sought to estimate the degree to which cannabis abuse is a risk factor for depressive symptoms rather than an effort to self-med icate depression. Method: Participants (N=1,920) in the 1980 Baltimore Epidemiologic Catchmen t Area (ECA) study who were reassessed between 1994 and 1995 as part of a f ollowup study provided the data. The analysis focused on two cohorts: those who reported no depressive symptoms at baseline (N=849) and those with no diagnosis of cannabis abuse at baseline (N=1,837). Symptoms of depression, cannabis abuse, and other psychiatric disorders were assessed with the Diag nostic Interview Schedule. Results: In participants with no baseline depressive symptoms, those with a diagnosis of cannabis abuse at baseline were four times more likely than t hose with no cannabis abuse diagnosis to have depressive symptoms at the fo llow-up assessment, after adjusting for age, gender, antisocial symptoms, a nd other baseline covariates. In particular, these participants were more l ikely to have experienced suicidal ideation and anhedonia during the follow -up period, Among the participants who had no diagnosis of cannabis abuse a t baseline, depressive symptoms at baseline failed to significantly predict cannabis abuse at the follow-up assessment. Conclusions: Further research is needed to identify characteristics of indi viduals who abuse cannabis that account for their higher risk of depression to estimate the degree of impairment resulting from their depression.