Diagnostic criteria for anti-social disorders have been much influenced by Robins's (1966) early findings that the central adult outcome of childhood conduct problems lies in the pattern of severe anti-social difficulties, evident across domains of functioning, typified by anti-social personality disorder (ASPD). Hyperactivity, impulsivity and attentional difficulties have consistently been identified as among the more important markers of poor long-term outcome for conduct problems, at least in males. For anti-social children and adolescents, new environmental demands, whether prompted by developmental transitions or situational stressors, may only go to reinforce deviant tendencies. For many anti-social children, adverse environments are likely to persist across development. Behaviour genetic analyses have begun to illuminate the interplay between heritable and experiential risks, and longitudinal studies are providing an increasingly detailed picture of the complex forces that shape lives through time.