Attention deficit disorder in children: three clinical variants.

A clinic-referred population of 116 children with attentional problems was classified by DSM-III [attention deficit disorder (ADD)] with respect to inattention, impulsivity, and hyperactivity. The sample proved to subdivide into three groups: inattentive, impulsive, and hyperactive (HII), n = 60; inattentive and impulsive (II), n = 26; and inattentive (I), n = 30. The distinction between II and I resolves the confounding of impulsivity and inattention in previous studies of children who have ADD but are not hyperactive. The three groups were found to be similar in mean age, gender ratio, prevalence, and pattern of associated learning disabilities, family history of psychopathology, and probability of favorable response to methylphenidate. Group I differed from Groups HII and II in the frequency of externalizing relative to internalizing comorbid psychopathology. A group that is hyperactive and impulsive but not inattentive was not found. The preponderance of similarities in associated characteristics suggests that the three groups are differing clinical presentations of an ADD spectrum.