That cannabis use shares risk and protective influences with the outcomes listed in (a)-(c) is evident (Figure 1C). For example, adolescent exposure to cannabis use often co-aggregates with other putatively deviant or precocious behaviors, such as conduct problems and early consensual sex, which in turn, are also associated with use of other illicit drugs (23–25). There are environmental factors, such as neighborhood characteristics (e.g. easy access to cannabis in a neighborhood that also promotes early delinquent activity), that bind these behaviors together (26; 27) and, importantly, also genetic influences. For example, numerous studies have shown that underlying early drug use and other problem behaviors is a general, highly heritable predisposition to externalizing behaviors (28; 29).
