Adderall XR is just extended release capsules which contain a combination of synthesized amphetamine salts that affect the CNS and help control ADHD or ADD. Snorting it would give you all the effects at once instead of a slow absorbtion from swallowing the capsule whole.

15 mg is not that high of a dose as some capsule contain doses over 30 mg. It has similar characterics of methamphetamine but its not exactly the same. Becareful with your medications and be sure not to overdose on your Adderall its not good for you.

P-Drugs 101 (CPhT)