Relation of attention deficit and conduct disorder to vigilance and reading lag.

The relationship between DSM-III Axis I diagnoses 'attention deficit disorder with hyperactivity' (ADDH), 'conduct disorder' (CD) and 'anxiety disorder' (AD) and measures of attention and reading were studied in 158 children. Children diagnosed as having severe or moderate ADDH were found to be younger at referral and to have a lower IQ than were children with CD and AD. When age, IQ, social class and sex were controlled, children with severe ADDH were found to perform significantly worse than other diagnostic groups on some tests of vigilance and reading age. The data suggest that children with severe ADDH form a distinct group, and those with mild ADDH overlap symptomatically and on tests of vigilance with children with CD.