The current study investigated gender differences in types and correlates of aggression among 150 adjudicated youth (M age = 15.2, SD = 1.4). In cluster analysis, consistent with past studies, one aggressive group characterized by moderate levels of reactive aggression and one characterized by high levels of proactive and reactive aggression…

The present study examined the joint development of substance use and externalizing problems in early and middle adolescence. First, it was tested whether the relevant groups found in previous studies i.e., those with an early onset, a late onset, and no onset or low levels of risk behavior could be identified, while using a developmental model of…