Peer rejection and aggression and early starter models of conduct disorder.

Peer rejection and aggression in the early school years were examined for their relevance to early starting conduct problems. The sample of 657 boys and girls from 4 geographical locations was followed from 1st through 4th grades. Peer rejection in 1st grade added incrementally to the prediction of early starting conduct problems in 3rd and 4th grades, over and above the effects of aggression. Peer rejection and aggression in 1st grade were also associated with the impulsive and emotionally reactive behaviors found in older samples. Being rejected by peers subsequent to 1st grade marginally added to the prediction of early starting conduct problems in 3rd and 4th grades, controlling for 1st grade ADHD symptoms and aggression. Furthermore, peer rejection partially mediated the predictive relation between early ADHD symptoms and subsequent conduct problems. These results support the hypothesis that the experience of peer rejection in the early school years adds to the risk for early starting conduct problems.