This study investigates characteristics of children and their environments that place them at risk for the development of disruptive behavior disorders and co-morbid internalizing problems (anxiety and mood disorders). Children ages 4-5 with moderate (subclinical) and high (clinical) rates of misconduct during the preschool period are compared with low risk children. Children and their families are studied again at four later time points: (a) early childhood (6-7 yrs.), (b) middle childhood (9-10 yrs.), (c) early adolescence (13-14 yrs.), and (d) mid-adolescence (15-16 yrs.). Assessments of children include dimensions of biological, cognitive, affective, emotional and behavioral functioning, that have been identified in research with older children as putative risk and protective factors in the development of conduct problems. Socialization experiences within and outside the family, also hypothesized to influence developmental trajectories are examined. Currently, Time 4 assessments are being conducted, with three-quarters of the research subjects tested. Behavior problems show significant stability across the first three time periods. However, some children improve over time, changes that result, in part, from more optimal environmental conditions. Different patterns of emotion dysregulation, ANS, and HPA activity in antisocial preschool children predict different types of externalizing problems at later time points. Behavior problems and their correlates differ for young disruptive boys and girls: Oppositional, aggressive girls are more likely to have co-morbid internalizing problems, and emotion regulation patterns that may decrease risk for continued antisocial behavior, but increase risk for depression and anxiety later in development.