Equivalent effects of stimulant treatment for attention-deficit hyperactivity disorder during childhood and adolescence.

OBJECTIVE

To compare the therapeutic effect size of methylphenidate on attention-deficit hyperactivity disorder (ADHD) during childhood versus adolescence.

METHOD

A retrospective follow-up study of 16 individuals with diagnosed ADHD who completed double-blind, placebo-controlled, crossover studies of methylphenidate 0.3 mg/kg during two separate summer treatment programs. The programs were completed when the subjects were children (aged 8 to 11 years) and adolescents (aged 12 to 14.5 years). Dependent variables include objective measures of academic performance and social behavior and ratings completed by counselors and teachers.

RESULTS

Effect sizes ranged from very large to small, with most effects in the moderate to large range. Across the 12 dependent variables, t tests found that only 3 showed statistically significant changes in effect size from childhood to adolescence. Putative changes in effect sizes can be dismissed for methodological reasons.

CONCLUSION

Stimulant medication is equally effective with children and adolescents with ADHD if they are engaged in similar activities. Treatment providers should rigorously examine environmental causes to problems before prescribing higher doses of stimulants to adolescents with ADHD who exhibit a worsening in functioning.