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.