Several areas of research propose alternate mechanisms underlying the liability for substance problems. One possible mechanism of risk specificity is that early involvement with alcohol in adolescence possibly increases the risk of later dependence by altering a person’s normal developmental trajectory (DeWit et al., 2000). Intuitively, the same claim could be made for all drugs of abuse, given their impact on the still developing adolescent brain. A possible mechanism for the generalized risk is the interaction of the neural pathways associated with addictive drugs and the mesolimbic dopaminergic system which is the target pathway for the reinforcing effects of drugs (Dick and Beirut, 2006; Gardner, 2002; Koob and Le Moal, 2001). From an environmental perspective, it is also possible that drug use and abuse in adolescence increases the possibility of continued exposure to high-risk environments which may limit the attainment of adult roles, impair physical and mental health, and foster the development of antisocial and criminal behaviors which are alternative pathways to addiction (Jessor, 1998; White et al., 1998).
