Childhood attentional and neuromotor precursors of social competence and affective deficits in adolescents at risk for schizophrenia, adolescents at risk for affective disorder, and matched comparison adolescents were examined. The subjects were offspring of parents with schizophrenia or affective disorder and of normal parents matched on age, sex, and socioeconomic status from the New York High-Risk Project (Sample B). On the basis of interviews conducted when the subjects were children and adolescents, social competence was rated from child reports and parent reports, affective deficits were assessed by affective flattening ratings, and smiling was assessed by counting broad smiles. Adolescents at risk for schizophrenia had significantly greater social and affective deficits than adolescents at risk for affective disorder and comparison adolescents. In subjects at risk for schizophrenia, childhood neuromotor dysfunction predicted adolescent affective flattening, and childhood attentional dysfunction predicted adolescent social deficits. The results suggest that affective and social deficits in schizophrenia have different childhood precursors.