Abstract
PURPOSE: The aim of the study was to help quantify the protective effects of stimulant treatment on important functional outcomes in attention-deficit/hyperactivity disorder (ADHD) using the number needed to treat (NNT) statistic and examine whether these effects are moderated by sex. METHODS: Subjects were derived from three independent samples, two similarly designed case-control, 10-year prospective follow-up studies of boys and girls with and without ADHD grown up and a cross-sectional randomized clinical trial of lisdexamfetamine on driving performance and behavior. For all studies, subjects were evaluated with structured diagnostic interviews. To measure psychopharmacologic treatment in the follow-up studies, we collected information about each subject's stimulant medication use, age at onset, and age at termination of treatment. Subjects in the driving study underwent two driving simulation assessments (premedication and after 6 weeks of treatment on lisdexamfetamine or placebo). For each outcome, we ran a logistic regression model that included an interaction between sex and treatment status. Lifetime rates were used to calculate the NNT statistic. We also calculated adjusted NNT statistics that accounted for sex, age, socioeconomic status, and family intactness. RESULTS: The NNTs were very low, ranging from 3 to 10. No interaction effects with sex were detected (all p > .05). The adjusted NNTs mostly remained the same with the exception of any substance use disorder, which increased after controlling for age. CONCLUSIONS: Stimulants have strong protective effects on functional outcomes in youth with ADHD that are not moderated by sex. These results support the critical importance of early identification and treatment of children with ADHD of both sexes.