I only know what my students have told me:
1) There is an apparent black market at my university for the pills. They're normally $4/pill and go up to $20/pill around exam time.
2) Some of my students do think that their friends are addicted to adderol; whether this is psychological (I can't only study if I've taken one) or physical (My brain isn't working; I need one) I don't know. None of them admitted to taking any themselves, and those in classes graded on a curve thought it was cheating.
So basically, I'm useless. But I do think your desire to get informed is a good one. Best not to be doing permanent damage unknowingly. Have you tried an internet search on the matter?
**Found the spelling: Adderall