Acute effects of caffeine in normal prepubertal boys.

A recent study demonstrated that dextroamphetamine has an effect in normal prepubertal boys similar to that seen in hyperactive children. The purpose of the present study was to see whether the effects of caffeine are similar to those of amphetamine in normal children. The authors observed 19 prepubertal boys following administration of a single dose of placebo, 3 mg/kg of caffeine, and 10 mg/kg of caffeine in a double-blind, crossover design. Caffeine produced increased vigilance and decreased reaction time, as does amphetamine. Unlike amphetamine, however, the higher dose of caffeine did not have a motor calming effect but increased motor activity. Separate biological systems, therefore, may be differentially affected by the two substances.