Nicotine addiction is the most common preventable cause of premature death presenting during adolescence. No prior study has described the onset of this condition based on case histories. We used trained personnel to conduct individual semi-structured interviews to obtain case histories from 50 adolescent and young adult current and former smokers. Smokers experience a compulsion to use tobacco that spans a spectrum of severity from wanting, to craving, to needing. The compulsion is commonly experienced as originating foreign to the will of the smoker and recurs with a predictable periodicity that determines the latency from smoking one cigarette to wanting, craving or needing another. Novice smokers could experience latencies as lengthy as a few weeks, and more experienced smokers attributed their escalation in smoking frequency to the shortening of their latencies. Wanting, craving or needing tobacco, as described in this study, are pathognomonic for a compulsion to use tobacco.