Neural Correlates of Polysubstance Use: Differential and Interactive Effects of Alcohol and Cannabis on the Adolescent Brain

Two of the most commonly used and abused substances by adolescents in the United States are alcohol and cannabis, which are associated with adverse medical and psychiatric outcomes. Alcohol use and cannabis use during adolescence is also associated with an increased risk of alcohol use disorder (AUD) and/or cannabis use disorder (CUD) in adulthood as well as increased likelihood of relapse after successful treatment. Despite this, much of the previous work on the neurobiology of substance use disorders has focused on adult substance use. This work has shown that individuals with AUD and/or CUD show dysfunction within reward processing, emotion processing, and executive functioning neuro-circuitries. In this dissertation, we have utilized the Monetary Incentive Delay (MID), Affective Stroop (aST), and Optimistic Bias (OB) tasks in order to examine dysfunction in these neuro-circuitries related to AUD and CUD symptomatology in a group of adolescents from a residential treatment facility and the surrounding community. The current data indicate that dysfunction in reward processing, emotion processing, and executive functioning neuro-circuitries is associated with AUD symptomatology, primarily within the MID and aST. However, dysfunction in emotion processing and executive functioning neuro-circuitries is associated with CUD neuro-circuitries across all three tasks. Moreover, there are interactive effects of AUD and CUD symptom severity on emotional processing and executive functioning neuro-circuitries within the aST and OB tasks. These data indicate differential and interactive effects of AUD and CUD on various neuro-circuitries within the adolescent brain