Gregory B. Bovasso, PhD, Assistant Professor of Behavioral Sciences at the Community College of Philadelphia, wrote the following in his Dec. 2001 article titled "Cannabis Abuse as a Risk Factor for Depressive Symptoms," published in the American Journal of Psychiatry:

“In participants with no baseline depressive symptoms, those with a diagnosis of cannabis abuse at baseline were four times more likely than those with no cannabis abuse diagnosis to have depressive symptoms at the follow-up assessment, after adjusting for age, gender, antisocial symptoms, and other baseline covariates.

In particular, these participants were more likely to have experienced suicidal ideation and anhedonia during the follow-up period.

Among the participants who had no diagnosis of cannabis abuse at baseline, depressive symptoms at baseline failed to significantly predict cannabis abuse at the follow-up assessment.”

Dec. 2001