2.2. Instruments
2.2.1. Smoking Habit Questionnaire
Before starting the psychological treatment all the smokers filled out the 56-item Smoking Habit Questionnaire , designed to gather information on both sociodemographic variables (gender, age, marital status, educational level) and tobacco use (i.e., number of cigarettes smoked per day).
2.2.2. Nicotine dependence
Information related to nicotine dependence was obtained at baseline through the Fagerström Test for Nicotine Dependence, in its validated Spanish version. This scale is made up of 6 items and the scores ranges from 0 to 10 points. The FTND is the most widely used instrument for rating nicotine dependence and it has been translated into numerous languages. Previous studies have confirmed the reliability of the FTND in different settings and populations. In the present sample the reliability obtained by means of Cronbach’s alpha was 0.59, indicating that the FTND has moderate internal consistency according to previous studies.