Background: Physical aggression is an important issue in North American populations. The importance of students' social environments in the occurrence of physical aggression requires focused study. In this study, reports of physical aggression were examined in relation to social environment factors among national samples of students from Canada…

The influence of using substances with friends on future individual use was examined in the context of parental monitoring rules and the ecology of peer activities. A 1-year longitudinal study design included a combined sample of North Italian and French Canadian adolescents (N = 285, 53% girls, M = 14.25 years). Data analyses were conducted using…