This might be a bit controversial and even if it does turn out to be useful for addiction therapy, that doesn't necessarily mean it will be for your friend. An

This might be a bit controversial and even if it does turn out to be useful for addiction therapy, that doesn't necessarily mean it will be for your friend. Anyway, when I was smoking tobacco every day (albeit only 1 pack a week) I took LSD for the first time at a very small dose (probably around 90µg) with a close friend. I wasn't doing it for any real reason except to see what it was like. Strange enough though afterwards I had no intention at all of continuing smoking tobacco and I now get extremely nauseous at the slightest smell of tobacco. You can find quite a lot of information on psychedelic therapy although a lot of research was halted after those drugs became stigmatised and illegal. There is a sort of psychedelic research renaissance occurring and there's been quite a few new studies on their usefulness.