An extended-release amphetamine suspension improved pediatric ADHD outcomes at assessments from one through 13 hours after dosing. Those observation points establish the tested window, not the precise minute effects began or ended.
Childress and colleagues evaluated children aged 6–12 in a dose-optimized randomized placebo-controlled study. A five-week open-label phase preceded a one-week double-blind comparison. The final laboratory classroom day used behavior ratings and mathematics performance. Ninety-nine patients completed the study. The controlled phase compared optimized doses of the suspension with placebo, rather than comparing all amphetamine formulations.
The primary four-hour change in classroom score favored active treatment. Significant differences also appeared at the scheduled secondary time points, including one hour, the earliest measurement, and 13 hours, the latest. Mathematics performance followed a similar pattern. Saying the drug worked ‘by the first measured hour’ preserves the design; claiming it first began working at exactly that hour would add information the study did not obtain.
The controlled period was short, and dose optimization was managed by experienced investigators. Required doses and exclusion of significant psychiatric comorbidity limit generalization. Decreased appetite, insomnia and mood-related adverse events were reported during optimization, so efficacy should not be summarized as absence of tolerability concerns. Classroom outcomes do not establish safe driving or universal cognitive enhancement. They also provide no direct conversion between a forensic drug concentration and function. The formulation, selected population, optimized dose and measurement schedule jointly define the evidence; changing any of those conditions requires additional support.
See why the dosing design matters in an ADHD trial.