RUNNING HEAD: Relationships and Externalizing Behavior Relations Between Childhood/Adolescent Family and Peer Relationships and Young Adulthood Externalizing Behavior Problems

The study of relationship antecedents of externalizing behavior problems has primarily focused on potentially harmful aspects of relationships such as conflict and hostility. Although a large body of literature has investigated the role of family and peer relationships in the development of externalizing behavior problems, few research efforts have focused on studying these relationship domains in conjunction. I investigated the relative role of family and peer relationships during middle childhood and adolescence in predicting externalizing behavior problems during young adulthood by analyzing data from the Minnesota Longitudinal Study of Parents and Children. Results showed that the quality of family and friendship relationships each uniquely predict young adulthood externalizing behavior problems, and that these effects cannot be accounted for by middle childhood peer competence. Second, results indicate that adolescent friendship quality does not account for the impact of adolescent family quality. In considering how the quality of relationship processes may affect change in externalizing behavior problems from age 16 to age 26, results showed that the quality of family relationships but not the quality of friendship relationships was a significant predictor of change in externalizing behavior problems.