Risk factors for conduct disorder and delinquency: key findings from longitudinal studies.

Conduct disorder (CD) and delinquency are behavioural problems involving violation of major rules, societal norms, and laws. The prevalence of CD and delinquency peaks in mid-to-late adolescence. Both show considerable continuity over time. The most important studies of CD and delinquency have prospective longitudinal designs, large community samples, repeated personal interviews, measures of many possible risk factors, and both self-reports and official measures of antisocial behaviour. The most important risk factors that predict CD and delinquency include impulsiveness, low IQ and low school achievement, poor parental supervision, punitive or erratic parental discipline, cold parental attitude, child physical abuse, parental conflict, disrupted families, antisocial parents, large family size, low family income, antisocial peers, high delinquency rate schools, and high crime neighbourhoods. However, for many risk factors, it is not known whether they have causal effects. Future research should examine changes in risk factors and changes in CD and delinquency to identify the risk factors that are causes and those that are merely markers of other risk mechanisms.