Supplementary Material for: Factor Analysis and Psychometric Properties of the Minnesota Nicotine Withdrawal Scale and the Minnesota Nicotine Withdrawal Scale-Revised: Italian Version

Background/Aims: We run Exploratory and Confirmatory Factor Analyses of the Minnesota Nicotine Withdrawal Scale (MNWS) and of the MNWS-Revised (MNWS-R). Psychometric properties were also explored. Methods: Adult Italian smokers, 366 in all, were assessed via the MNWS-R together with rating scales measuring cigarette dependence, alcohol use, anxiety sensitivity and negative affect at baseline and after 3 months. Results: The MNWS showed good psychometric properties (α = 0.85; rtt = 0.59) and a unidimensional factor structure. The 2-factor model of MNWS-R had the best fit and the factors were labelled psychological symptoms (α = 0.86; rtt = 0.59) and associated somatic features (α = 0.64; rtt = 0.45). Conclusions: MNWS showed 1 factor; MNWS-R showed 2 relatively dependent factors. The results need to be replicated in smokers in withdrawal.