Methylphenidate effects on a laboratory aggression measure in children with ADHD.

This study investigated the utility of the Point Subtraction Aggression Paradigm (PSAP), a computerized laboratory analog aggression measure. We measured the effects of methylphenidate (MPH) on aggressive responding in children with a DSM-III-R diagnosis of attention deficit hyperactivity disorder (ADHD), who had high ratings on the Child Behavior Checklist Aggression Factor (CBCL; Achenbach 1991). Results are reported for 6 subjects, ages 8-11 years. All were tested at baseline in an unmedicated condition, and after double-blind administration of placebo, 0.3 mg/kg of MPH, and 0.6 mg/kg of MPH. A main effect of decreased aggressive responding with MPH was found, with a dose-related change by repeated measures ANOVA (F = 6.59, df = 2.10, p = .014). Post-hoc analysis with the Tukey HSD indicated that only the 0.6 mg/kg was significantly (p < .05) different than placebo. Implications for use of the PSAP in future investigations of medications in aggressive children are discussed.