A twin study of hyperactivity--I. An examination of hyperactivity scores and categories derived from Rutter teacher and parent questionnaires.

In a representative sample of 570 13-yr-old twins, higher hyperactivity scores from parent and teacher ratings were associated with male sex, lower intelligence, inattention, specific learning problems, and behavioural deviance (mainly antisocial). This pattern of correlates also characterized all three hyperactivity categories: to a marked degree in pervasive hyperactivity; less markedly in school hyperactivity; and least markedly in home hyperactivity. Children with pervasive hyperactivity had more attentional and educational problems than non-hyperactive children who were pervasively antisocial. By contrast, children with school or home hyperactivity resembled non-hyperactive children who were situationally antisocial. These findings cast doubt on the validity of combining situational and pervasive hyperactivity into a single diagnostic category such as Attentional Deficit Disorder with Hyperactivity (ADDH).