A controlled study of siblings of hyperactive children.

A controlled study of siblings of hyperactive boys resulted in the following findings. The hyperactive child syndrome is more common among brothers of hyperactive children than among brothers of controls (26 per cent vs. 9 per cent). Both probands and their brothers presented with more symptoms of depression-anxiety than controls. The probands, but not their sibs, presented with more antisocial symptoms than controls. Although differences in intelligence and achievement scores were found between probands, their sibs, and controls, both intelligence level and academic achievement were within normal limits in all groups.