Background: Early substance use co-occurs with youths' self-organization into deviant peer groups in which substance use is central to social interaction. We hypothesized that the social dynamics of deviant peer groups amplify the risk of progressing from early use to later dependence, and that this influence occurs over and above escalations…

This study investigated the development of mother-son relationship quality from ages 5 to 15 in a sample of 265 low-income families. Nonparametric random effects modeling was utilized to uncover distinct and homogeneous developmental trajectories of conflict and warmth; antecedents and outcomes of the trajectory groups also were examined. Four…

Explores developmental and intervention evidence relevant to iatrogenic effects in peer-group interventions. Findings from two intervention studies involving 119 high-risk youth and 39 controls and 150 pairs of adolescent boys suggest that high-risk youth are particularly vulnerable to peer aggregations when compared to low-risk youth. Discusses…