Many of these concomitants are consistent with early risk markers for eventual substance use in adolescence, particularly those that indicate continued and even escalating problems with emotional and social adjustment. Challenges associated with social interaction may lead children with greater internalizing symptoms over time to become socially rejected and isolated as they progress through the school years (Lillehoj, Trudeau, Spoth, & Wickrama, 2004). Although the relation between social withdraw in early childhood and later substance use has not been directly explored in the literature, peer rejection in the grade school years is associated with later internalizing symptoms in adolescence (Coie, Lochman, Terry, & Hyman, 1992). Moreover, the early emerging socio-cognitive processing style associated with internalizing symptoms and social withdrawal may further entrench and even exacerbate risk for increasing internalizing symptoms through the middle childhood years. Based on these findings, we posit that the early manifestations of the internalizing pathway to SUDs include high behavioral inhibition (in infancy), elevated internalizing symptoms (including both anxiety and depression, emerging with toddlerhood), and subsequent increases in peer rejection, social withdrawal and disengagement (exacerbated at school entry).
