Adolescence is a period of both risk and resilience regarding the harms of cannabis use. This systematic review examined whether age (adolescent vs. adult) moderates the relationship between cannabis exposure and cognition, drawing on both human and animal studies. The review does not offer a conclusive answer but generates four hypotheses: general executive functioning appears more impaired in adolescent frequent users than in adult frequent users; age effects may be strongest among very heavy and dependent users; craving and inhibitory control may not decrease as much post-intoxication in adolescents; and adolescents' vulnerability to reduced learning following cannabis use may not persist after sustained abstinence. If confirmed, these hypotheses could inform policy and prevention.
Near-daily cannabis users had lower resting-state functional connectivity within the dorsal salience network compared to non-users, and lower connectivity in that network was linked to heavier cannabis use. Cultural attitudes—personal, friends-and-family, and country-level—moderated how strongly cannabis use, cannabis use disorder symptoms, and cannabis-related problems were associated with connectivity in the salience, executive control, and default mode networks. No group differences emerged in between-network connectivity, but personal perceived benefits and country-level perceived harms moderated the link between disorder symptoms and connectivity between two default mode subnetworks. The authors conclude that individual differences in perceived harms and benefits of cannabis should be considered when studying brain–behavior relationships.