Continuity of aggressive antisocial behavior from childhood to adulthood: The question of phenotype definition.

Aiming to clarify the adult phenotype of antisocial personality disorder (ASPD), the empirical literature on its childhood background among the disruptive behaviour disorders, such as attention deficit/hyperactivity disorder (AD/HD), oppositional defiant disorder (ODD), conduct disorder (CD), or hyperkinetic conduct disorder (HKCD), was reviewed according to the Robins and Guze criteria for nosological validity. At least half of hyperactive children develop ODD and about a third CD (i.e. AD/HD+CD or HKCD) before puberty. About half of children with this combined problem constellation develop antisocial personality disorder (ASPD) in adulthood. Family and adoption/twin studies indicate that AD/HD and CD share a high heritability and that, in addition, there may be specific environmental effects for criminal behaviours. "Zones of rarity" delineating the disorders from each other, or from the normal variation, have not been identified. Neurophysiology, brain imaging, neurochemistry, neurocognition, or molecular genetics have not provided "external validity" for any of the diagnostic categories used today. Deficient mental functions, such as inattention, poor executive functions, poor verbal learning, and impaired social interaction (empathy), seem to form unspecific susceptibility factors. As none of today's proposed syndromes (e.g. AD/HD or psychopathy) seems to describe a natural category, a dimensional behavioural phenotype reflecting aggressive antisocial behaviours assessed by numbers of behaviours, the severity of their consequences and how early is their age at onset, which will be closely related to childhood hyperactivity, would bring conceptual clarity, and may form the basis for further probing into mental, cognitive, biological and treatment-related co-varying features.