High and stable levels of aggression and the presence of aggressive behaviour in multiple settings according to different informants are risk factors for later problems. However, these two factors have not been investigated in early childhood. The present study investigates trajectories of parent-reported child aggression from 1.5 up to 6 years of…

Using data from 1,676 youth who participated in three waves (Grades 6 to 8) of the longitudinal, 4-H Study of Positive Youth Development, we tested two series of hierarchal linear models to examine the role of peer support, associating with "problem-behaving" friends, and bullying involvement in the development of behavioral and emotional school…