2.3. Procedure
The initial assessment of all smokers was carried out in one session, during which a face-to-face interview and the abovedescribed instruments were administered. All the smokers gave their informed consent for participation, and the study was authorized by the Bioethics Committee of the University of Santiago de Compostela.
Next, the Smoking Cessation Program, a psychological cognitive-behavioral treatment, was administered. It is a standardized and manualized treatment program consisting of six sessions (one per week), and is administered in group format. It is made up of the following elements: treatment contract, selfreport and graphic representation of cigarette consumption, information about tobacco, stimulus control, activities for the avoidance of withdrawal syndrome, physiological feedback (CO in expired air) on cigarette consumption, nicotine fading (change of cigarette brands each week progressively decreasing the intake of nicotine and tar), and relapse-prevention strategies. The groups were made up of 6–8 participants, assigned according to their own availability. Sociodemographic and smoking behavior characteristics were not taken into account for this purpose. Groups were attended by six different psychologists, and no differences were found in treatment results according to the therapist assigned to the group.
After the treatment there was a face-to-face follow-up at 12 months. Self-reported abstinence at the end of treatment and in the follow-up was tested by measures of CO in expired air. In those cases in which it was not possible to locate the participants, they were considered to be smokers, and at the same level (in terms of number of cigarettes and nicotine content) as in the pre-treatment assessment.