Modafinil vs Adderall: An Evidence-Based Comparison

Both are prescription cognitive enhancers, but they work through very different mechanisms — and have very different risk profiles.

Mechanism

Modafinil is a eugeroic — it promotes wakefulness via dopamine reuptake inhibition, orexin/hypocretin modulation, and histamine activation. Adderall (mixed amphetamine salts) is a direct stimulant that releases dopamine and norepinephrine from synaptic vesicles.

Efficacy

For ADHD, Adderall has decades of evidence as a first-line treatment. For shift-work sleep disorder and non-ADHD cognitive enhancement under sleep pressure, modafinil has more focused evidence (Battleday & Brem 2015 systematic review).

Side Effects

Modafinil: headache (~20–30%), nausea, anxiety. Rare Stevens-Johnson syndrome. Reduces hormonal contraceptive efficacy.

Adderall: insomnia, appetite suppression, elevated heart rate and blood pressure, anxiety. Significant abuse potential — Schedule II in the US.

Legal Status

Modafinil is Schedule IV in the US; Adderall is Schedule II. Both require prescription in virtually every jurisdiction.

When Each Wins

Modafinil for sustained alertness without euphoria, prescribed shift-worker support, or executive function under sleep pressure. Adderall for clinically diagnosed ADHD where direct dopamine release is the goal.