Behavioral effects of caffeine and other methylxanthines on children.

Subjective, performance-enhancing, dependence-producing, and adverse effects of methylxanthines are examined, based on computerized searches (i.e., Medline and PsycLIT). High doses (> 3 mg/kg) of caffeine in children who consume little caffeine produce negative subjective effects such as nervousness, jitteriness, stomachaches, and nausea. Whether lower doses produce positive subjective effects has not been adequately tested. Caffeine appears to slightly improve vigilance performance and decrease reaction time in healthy children who habitually consume caffeine but does not consistently improve performance in children with attention deficit-hyperactivity disorder. Early studies suggest caffeine self-administration and withdrawal can occur in some adolescent soda drinkers.