Do hyperactive children and their siblings differ in IQ and academic achievement?

To test the hypothesis that intellectual deficits are traits shared by family members of hyperactive children, 18 hyperactive children were compared to their nonhyperactive siblings on measures of intellegence and academic achievement. As measured by the Wechsler Intellegence Scale for Children, the nonhyperactive siblings had significantly higher Verbal, Performance, and Full Scale IQs. Scores on the Wide Range Achievement Test and the Gray Oral Reading Test did not differ between the groups when adjusted for IQ. Contrary to previous hypotheses, the data suggest that intellectual deficits may be specific to hyperactive children and not a familial trait.