Thanks for quoting the backing research and it looks very sound. Now I am curious about how do they even begin. I know it's a naive question, but it's not like somebody is "prescribing" them to smoke or use nicotine. I can make sense (barely) of the behavior after smoking the first cigarette, but before that, a person, in general, should be unaware of its consequences. I am geniunely curious about what motivates such individuals to take the leap from 0 to 1.