SmokingStudies of ex-smokers show that their risk of dying from smoking-related disease decreases with each year of non smoking. Encouraged by such evidence, more than 40 million people in the U.S. quit smoking in the year following the 1964 surgeon general's report. The proportion of males who smoke decreased from more than 60 percent to about 25 percent; however, the percentage of women who smoke cigarettes increased. Smoking also became more prevalent among young adults, with about 29 percent of high school seniors admitting to smoking in 1975; but by 1987 this proportion decreased to 18.7 percent. There are programs that exist to help smokers quit. Some involve group support, whereas others use aversive techniques in which participants smoke many cigarettes rapidly to the point of becoming sick of them.

More than 30 million persons in the U.S. say that they would like to quit smoking but cannot. One hypothesis to explain this problem is that the smoker craves the effect of the nicotine in the smoke. In a 1988 report, the surgeon general declared nicotine to be an addictive drug comparable to other addictive substances in its ability to induce dependence. The report also called the monetary and human costs far greater than those attributable to cocaine, alcohol, or heroin. Attempts to help persons quit smoking through counseling, participation in support groups, and, for those with a strong physical dependence on nicotine, substitution of chewing gum containing nicotine to lessen withdrawal symptoms.