Validity of the Italian version of the Severity of Dependence Scale (SDS) for nicotine dependence in smokers intending to quit.

The objective was to test the psychometric properties of an Italian version of the Severity of Dependence Scale, a five-item measure designed to assess the compulsive dimension of drug dependence. 635 smokers enrolled in a tobacco dependence treatment program served as the participants. The Fagerström Test for Nicotine Dependence was used as a comparative measure. Dimensionality of the Severity of Dependence Scale and the Fagerström Test for Nicotine Dependence was assessed by factor analysis. Prediction of smoking at one year was evaluated by logistic regression. Factor analysis yielded a two-factor solution; however, the second factor explained very little variance. Factor 1 had a Cronbach's alpha of .66 (overall Scale coefficient = .44). The total Severity of Dependence Score predicted smoking at one year (OR = 1.10).