Experienced amphetamine users are not able to distinguish the effects of amphetamine (Adderall) and methamphetamine (Desoxyn) in double-blind "taste tests". The main difference is that the effective dosage is different.

It's easy to abuse amphetamine in the catastrophic ways that methamphetamine is abused: you crunch it up and snort it instead of taking a slower-releasing pill, and you take higher dosages than you'd take to focus on your homework.