Grant: Team Grant: Cannabis Research in Priority Areas - Mental Health

There is significant public concern over the impact of cannabis use during adolescence on the developing brain and potential subsequent risk for the development of mental illness. Surprisingly, the evidence gathered to date is quite inconclusive with some individual studies showing adverse impacts of cannabis use while many others showing no effect at all. As such, it is likely that there are specific variables that influence how cannabis use during adolescence modulates these outcomes. This study will use a novel, translationally relevant rodent model of adolescent exposure to cannabis vapor we will be able to explicitly test the impact of cannabis exposure on adolescent brain development using a titrated scale of exposure to cannabis during adolescence, ranging from infrequent use to multiple times per day of high potency cannabis. We will employ repeated testing of magnetic resonance imaging of structural brain development, electrophysiology, behavioural tasks and stress reactivity to determine how exposure to varying levels of cannabis during adolescence impacts neurodevelopment trajectories during this window. We will also explore how additional exposure to early life adversity or concomitant social stress during adolescence, influences the impacts of daily exposure to cannabis on structural brain development and behavioural outcomes. The patterns of cannabis use we will be modelling are guided by our collaborative work with our partners in public health who studies adolescent cannabis use to ensure we are modelling realistic and relevant patterns of cannabis use. These rodent studies will be complimented by integrating with a prospective cohort study of adolescents at high risk for mood disorders, to explore the impacts of cannabis initiation on brain development and the development of any psychiatric illnesses. These studies will help us to establish if there are clear harms associated with cannabis use during adolescence on the development of mental illness.