In this proposal, a theoretical model is developed which considers the role of Callous-Unemotional (CU) traits in the development and persistence of conduct problems. In this theory, CU traits are related to a specific temperamental style: low behavioral inhibition. Once CU traits develop, it places the child at high risk for developing a severe and chronic pattern of antisocial behavior. In this theory there are other pathways involving other etiological factors (e.g., family dysfunction, low intelligence, economic disadvantage, hostile attributional bias, that can lead to conduct problems in children without CU traits. However, to understand the role of these etiological factors in the development of antisocial behavior, their interaction with CU traits must be considered. For example, in a pilot study, maladaptive parenting was found to be associated with the development of conduct problems only in the absence of CU traits. Also in this theory, CU traits are used to explain some of the variations in the developmental trajectories of conduct problem behavior. Children with CU traits are predicted to account for a significant number of boys with an early onset of conduct problems who show an especially severe and persistent pattern of antisocial behavior. The model also attempts to explain gender differences in these developmental trajectories, with girls who show CU traits in childhood being at risk for showing overt antisocial in adolescence. Several testable predictions that follow from this conceptual model are the focus of the proposed study which will be conducted in three phases. The first phase will involve a large community sample of school-aged children in two grade cohorts, grades 3 and 4 (n=800) and grades 6 and 7 (n=800). These children will be screened on a measure of CU traits and on a measure of conduct problems. From this community sample, a smaller sample of children (n= 160) will be recruited to fill a 2 X 2 factorial design with high versus low scores on a measure of the CU traits and high versus low scores on a measure of conduct problems forming the two factors. This select sample of children will be the subject pool for the next two phases of the project which involves an initial in depth assessment followed by yearly follow-up assessments over the ensuing three years.