The study has focused on the frequency of antisocial acts across the adolescent years, the frequency of antisocial acts among males and females, patterns of antisocial behavior over time, predictors of antisocial behavior across time and across domains of functioning, and gender differences in the predictors of antisocial behavior. The study has found that some degree of antisocial behavior is common among adolescents; however, there are distinct patterns both in the timing, the frequency, and the nature of the antisocial behaviors; these must be taken into account by prevention strategies. The findings suggest that early interventions to divert children from pathways to persistent antisocial behavior are most appropriate during the primary school years for most youth. Those youth who engaged in persistent antisocial behavior during adolescence were found to be consistently more aggressive, more disinhibited, and more temperamentally reactive from mid-childhood onwards than youth who later engaged in little or no antisocial behavior. The report advises that interventions that target experimental antisocial behavior must be multifaceted and focus on the early secondary school years. Other findings were that precursors of antisocial behavior were similar for males and females; the character of peer relationships strongly influenced the level and degree of antisocial behavior; family environment was important in determining the character of antisocial behavior; and school adjustment and bonding were important factors in patterns of antisocial conduct. Overall, the most important factors that determined the patterns of antisocial behavior were related to temperament, behavioral problems, social skills, levels of risk-taking behavior and coping skills, school adjustment, peer relationships, and family environment. 12 tables, 11 figures, and 34 references