The Relationship Between Mental Health Symptoms and marijuana consequences mediated by coping motives for marijuana use

As marijuana continues to be legalized across the United States, it is imperative to investigate risk factors and consequences related to use. Previous studies among adult samples have found that mental health symptoms, including both depression and anxiety symptoms, are significant predictors of increased frequency of marijuana use. Little is known however regarding mental health symptoms and marijuana use among adolescents. This risk is particularly salient for adolescents given that many mental health disorders, like depression and anxiety, begin to emerge during this developmental period, and because earlier of age of marijuana use onset is associated with worse prospective health outcomes. Further, coping motives for marijuana use (i.e., using marijuana as an external avoidance or escape-based strategy) may serve as a mechanism for some adolescents to avoid distressing anxiety and depressive states. To address this gap in research, the aims of the current analysis were to 1) examine associations between mental health symptoms, marijuana use, and consequences among adolescents, and 2) examine coping motives as a mediator between mental health symptoms and marijuana outcomes. The current study included 107 late adolescents (15-18 years old, Mage = 17.01, SDage = 0.92, 51% female, 85% White/Caucasian, 60% high school student, 27% college student) recruited from Washington State. The sample was stratified by gender and marijuana use such that participants ranged from reporting infrequent to daily marijuana use. Participants were asked to complete three online assessments across six months. These included the PHQ-4, a 4-item measure of depression and anxiety symptoms in the past 2 weeks, in addition to measures of marijuana use, marijuana-related consequences, and marijuana use motives. We conducted two separate mediator models to examine if baseline mental health symptoms were mediated by coping motives at month 3 on (1) marijuana use and (2) marijuana-related consequences both reported at month 6. There was no significant mediation effect for baseline mental health symptoms predicting overall marijuana use at month 6 (B = .27, SE = .25, 95% CI [-.23, .76], p = .28). For the second model, motives at month 3 fully mediated the relationship between mental health symptoms at baseline and marijuana-related consequences at month 6 (B = .71, SE = .27, 95% CI [.17, 1.24], p ≤ .01). Thus, higher levels of mental health symptoms at baseline were associated with higher marijuana-related consequences as mediated by coping motives reported at month 3. Our results suggest that adolescents who experience more mental health symptoms do not use marijuana more than others who report fewer symptoms. However, these individuals may be at greater risk for experiencing negative consequences that result from their use. Further, results also suggest that the relationship between mental health symptoms and negative consequences may be largely accounted for by stronger motives to use marijuana to cope with mental health. Screening for mental health symptoms during adolescence may be beneficial in preventing negative outcomes by providing early interventions for healthy coping strategies for anxiety and depression.