Do people really bother "microdosing on Adderall"? The drug companies have already handled that bit for you. That's what Adderall XR is (and in a funkier way, Vyvanse, also): Adderall that is manufactured in such a way that it will enters your system a little at a time.
I dunno, I know a lot of people that are prescribed stonking doses of the high-test original formula, and break their tabs into quarters or eighths. Then again, the going rate in the cubicle streets is, I've been told, $30-$50 a pill, so that might have something to do with it.
