Exercise, Decision-Making, and Cannabis-Related Outcomes among Adolescents

Objective: Poor decision-making may represent a risk factor for adverse cannabis-related outcomes, whereas exercise has been linked to better executive functioning and substance use outcomes. This study examines the associations between self-reported exercise and cannabis use (CU) outcomes over 6 months among adolescents, and whether these are mediated by exercise-related effects on decision-making. Method: Participants were 387 adolescents aged 15-18 who completed two assessments 6 months apart. Self-reported past 6-month hours/week of exercise were assessed at baseline. At the 6-month follow-up, participants completed measures assessing past 6-month CU frequency, presence of CU disorder (CUD), and CU-related problems, as well as risky decision-making tasks (Iowa Gambling Task, Game of Dice Task, Cups Task), which were used to derive a latent construct of decision-making. We used prospective mediation to examine the role of decision-making in the relationship between exercise and CU outcomes. Results: More self-reported exercise at baseline predicted greater CU frequency at the 6-month follow-up, but did not predict the presence of a CUD, or cannabis-related problems. After controlling for confounds, baseline exercise did not predict better decision-making at follow-up. Decision-making did not predict CU outcomes, and indirect effects of decision-making were not significant. Conclusions: Contrary to hypotheses, adolescents reporting more exercise at baseline also reported higher CU frequency in our sample. This association may be explained by factors like sample characteristics or sports types, but more research is needed to explore this. Results did not support a mediating role for decision-making in the associations between exercise and CU outcomes.