Controlled smoking for chronic smokers: an extension and replication.

Nine long-term cigarette smokers participated in a seven session controlled smoking program. Employing a multiple baseline across behaviors design, the program focused on making sequential reductions in nicotine content of the cigarette brand smoked, percent of each cigarette smoked and, finally, number of cigarettes smoked per day. Self-monitoring records indicated that subjects were successful in making reductions in each of the three target behaviors and that the timing of these changes closely followed the initiation of treatment for each specific behavior. The magnitude of change was greatest for nicotine content (49% reduction) and somewhat less for number of cigarettes (28% reduction) and amount smoked (24% reduction). Carbon monoxide levels were also reduced and these reductions, as well as the smoking behavior changes, were generally maintained at a 6-month follow-up. This study provides a systematic replication of an earlier study and illustrates the usefulness of single subject designs for studying cigarette smoking. It is concluded that controlled smoking can be achieved by chronic smokers without significant relapse or compensation for at least six months following treatment. Limitations of the study and directions for future research are also discussed.