I had a friend get super skinny off adderall. we were the same way, I was on ritilan and neither of us could eat unless we smoked. it was fucking terrible.
i got off my meds way before he got of his adderall though. he's doing much better now.
here's the classifications etc...
Erowid Amphetamine (Adderall) Vault
C9H13N - adderall
C10H15N - meth
that's the chemical composition of both.