Objective: To determine by meta-analysis the effect size for stimulants on overt and covert aggression-related behaviors in children with attention-deficit/hyperactivity disorder (ADHD), separately from stimulant effects on the core symptoms of ADHD.
Method: A review of the literature from 1970 to 2001 revealed 28 studies meeting inclusion/exclusion criteria for meta-analysis. These studies yielded 28 independent effects of overt aggression and 7 independent effects of covert aggression.
Results: The overall weighted mean effect size was 0.84 for overt and 0.69 for covert aggression related behaviors in ADHD. Comorbid conduct disorder is associated with diminishing stimulant effect size for overt aggression.
Conclusion: Stimulant effects for aggression-related behaviors in ADHD have effect sizes similar to those for the core symptoms of ADHD.