Grant: Project Grant

With increases in cannabis use and rates of cannabis use disorder (CUD) in Canada, understanding the biobehavioural determinants of cannabis risks and harms can inform treatment and policy. As an individual becomes addicted to cannabis, they increasingly respond more to cannabis-related cues, and less to non-cannabis cues. An established determinant of CUD is overvaluation of cannabis, which is typically measured by cannabis demand, a behavioural economic measure of an individual's value of cannabis as a reinforcer. The current proposal applies neuroeconomic principles to understand cannabis demand choice behaviour in CUD. This approach sheds light on how much an individual values cannabis. The overall goal is characterizing neural activity associated with choices on a Marijuana Purchase Task (MPT) adapted for neuroimaging. The first aim investigates how the brain represents cannabis value as measured by cannabis demand in individuals with CUD compared to a matched control group. Given that the role of sex differences in CUD is under-investigated, the second aim focuses on clarifying neurobiological differences between males and females. Finally, a third aim investigates the relationship between neural activity patterns during cannabis demand decision-making and an intervention response. Participants in the CUD group will receive a motivational interviewing intervention and MPT neural activity will be used to predict subsequent cannabis use at 1-month and 6-month follow-up. Secondary aims include exploring specific cannabis compound influences via a quantitation of urinary cannabinoid metabolites. Collectively, these aims shed light on the neural underpinnings of cannabis demand and sex differences in relation to a clinical intervention. This neuroeconomic approach can substantially advance the understanding of motivation and behaviour change in CUD.