Marijuana Use and Depressive Symptoms among Young People: Examining Unidirectional and Bidirectional Effects

Abstract

Research suggests that the prevalence of marijuana use and depression are increasing in the United States. Although it is not entirely clear what accounts for these coincident trends, several studies have shown that these two health concerns are associated among young people. This study assessed four hypotheses regarding the association between marijuana use and depression: 1) whether marijuana use affects subsequent symptoms of depression; 2) whether depressive symptoms affect subsequent marijuana use; 3) whether they are associated in a bidirectional (reciprocal) manner; and 4) whether the association between the two is confounded by stressful life events. Using eight years of longitudinal data from the Family Wellness and Health Study, a fixed-effects regression model provided empirical support for the first hypothesis only, but not for the others. Future research should explore in greater detail why marijuana use may have a causal impact on experiences with depression among young people.