A 30-month study evaluated the degree of addic tion that teenagers form to nicotine once they begin experimenting with smoking." The study used a random sample of 332 seventh-grade stu- dents in two Massachusetts cities who had ever used tobacco by the start of the study. The response variable was constructed from the Hooked on Nicotine Checklist (HONC). This is a list of ten questions such as "Have you ever tried to quit but couldn't?" The HONC score is the total num- ber of questions to which a student answered yes. The higher the score, the greater the dependence on nicotine. There were 75 smokers and 257 ex- smokers at the end of the study. The HONC means describing nicotine addiction were 5.9 (s - 3.3) for the smokers and 1.0 (2.3) for the ex- smokers.