Hyperactivity: prevalence and relationship with conduct disorder.

This paper reports the prevalence of situational and pervasive hyperactivity using different definitions of 'caseness', and explores the relationship between situational and pervasive hyperactivity and conduct disorder, using a large data base from the North of England. The prevalence of hyperactivity, and its relationship with conduct disorder, varied according to whether hyperactivity was pervasive or situational, according to the age of the child and to the definition of hyperactivity 'caseness'. Among younger children only, school based situational and pervasive hyperactivity had comparable comorbidity with other available evidence of psychiatric disorder and hyperactivity was virtually a prerequisite for conduct disorder. Among older children, pervasive hyperactivity had greater comorbidity with other psychiatric disorder than situational hyperactivity and, furthermore, displayed the strongest links with conduct disorder.