My friend has been snorting vyvanse (lisdexamfetamine). he wants to quit. what should we expect for withdrawal symptoms? is there any danger?

Depends on amount: Snorting stimulants is probably more common than we realize. Vyvanse (lisdexamfetamine) is a type of amphetamine, like speed. Amphetamine withdraw includes anxiety, agitation or excessive fatigue. We always recommend a physician be involved when someone is stopping a habit such as amphetamines. I hope your friend is able to stop without withdrawing. Good luck.

Meth Addiction: Sounds like a methamphetamine addiction. There are multiple dangers with snorting this as well as quitting. You need to seek help with a detoxification clinic immediately before "your friend" overdoses or dies from the addiction and withdrawal symptoms.