A small study found that improvements from a no-drug baseline did not establish a specific cognitive benefit of amphetamine–dextroamphetamine over placebo. The appropriate comparator changed the interpretation of apparent enhancement.
Twenty-one college students without ADHD completed a no-drug baseline and sessions involving placebo or 10 mg immediate-release amphetamine–dextroamphetamine. The capsule sessions were counterbalanced, while baseline was a separate earlier assessment.
Objective tasks and self-reported or subjective functioning were examined. This controlled human experiment addressed enhancement in selected students without ADHD; it did not test treatment of diagnosed ADHD.
Most measures did not differ significantly across sessions. On a continuous-performance task, discrimination improved under both active drug and placebo relative to baseline, without a significant active-versus-placebo difference. A commission-error comparison favored placebo over baseline.
Post hoc order-adjusted results further complicated the apparent changes over time. Practice, repeated testing and expectations therefore remain relevant explanations. A before-and-after improvement alone cannot identify the pharmacological contribution.
The study tested one dose and formulation in a small sample, with power focused on medium or large effects. It cannot exclude smaller effects or generalize to every dose, task or population. Meals were not standardized, and some subjective assessments occurred at least a day after sessions began.
The evidence does not establish improved grades or performance during prolonged sleep loss. It also supplies no individual impairment threshold. Its methodological contribution is clear: compare active drug directly with placebo, and preserve the distinction between a significant baseline change and a demonstrated drug advantage.
See a separate healthy-student Adderall pilot.
Effects of Stimulant Medication on Neuropsychological Functioning in College Students without ADHD. doi:10.1037/pha0000853.