Cannabis, Connectivity, and Coming of Age: Associations between Cannabis Use and Anterior Cingulate Cortex Connectivity during the Transition to Adulthood

BackgroundCannabis use is common among adolescents and emerging adults and is associated with significant adverse consequences for a subset of users. Rates of use peak between the ages of 18-25, yet the neurobiological consequences for neural systems that are actively developing during this time remain poorly understood. In particular, cannabis exposure may interfere with adaptive development of white matter pathways underlying connectivity of the anterior cingulate cortex, including the cingulum and anterior thalamic radiations (ATR).\n\nMethodsThe current study examined the association between cannabis use during adolescence and emerging adulthood and white matter microstructure of the cingulum and ATR among 158 male subjects enrolled in the Pitt Mother & Child Project, a prospective, longitudinal study of risk and resilience among men of low socioeconomic status. Participants were recruited in infancy, completed follow-up assessments throughout childhood and adolescence, and underwent diffusion imaging at age 20 and 22.\n\nResultsAt age 20, moderate cannabis use across adolescence (age 12-19) was associated with higher fractional anisotropy of the cingulum and ATR, relative to both minimal and heavy adolescent use. Longitudinally, moderate and heavy extended cannabis use (age 12-21) was associated with reduced positive change in FA in both pathways from age 20 to 22, relative to minimal use.\n\nConclusionsThese results suggest that precocious white matter development may be linked to increased risk for use, whereas cannabis exposure may delay white matter maturation during the transition to adulthood and potentially impact individuals functioning later in development.