Isn't adderall basically prescription meth, anyway?
Adderall is normally prescribed in the XR formulation (meaning it's an extended/slow release capsule), and has amphetamine as the active ingredient.
Methamphetamine is a different molecule altogether, and typically it's not packaged in slow-release capsules.
Yes, methamphetamine is structurally related to amphetamine, but you shouldn't make the mistake to think they are interchangeable. Very often the difference between two very similar molecules is the difference between life and death (for a classic example, look up the two enantiomers of thalidomide).