Validation of a short Italian version of the Barratt Impulsiveness Scale (BIS-15) in non-clinical subjects: psychometric properties and normative data

Introduction: The Barratt Impulsiveness Scale (BIS) is a questionnaire employed to measure impulsivity, which is associated with risky behaviors and mental disorders. We aimed to assess the psychometric properties of the BIS in the Italian general population and provide normative data for clinical use. Materials and methods: A cross-sectional survey methodology was employed to collect data. Then, 534 participants of different ages and educational levels completed the BIS, PHQ-9, GAD-7, and S-UPPS-P. We designed an ad hoc data-driven outcome checklist to identify which items deserved to be retained. Furthermore, internal consistency, convergent and divergent validity, and factorial structure were evaluated. A regression-based procedure was used to explore the influence of demographic variables on the BIS score and to provide adjusting factors and a sensitive cutoff. Results: Item analysis suggested removing 15 items. Consequently, we tested the psychometric properties of a shorter version of the BIS (BIS-15). IRT test information functions indicated an almost identical measurement precision of the BIS-15 as compared to the original BIS. The BIS-15 demonstrated reliable internal consistency and good convergent and divergent validity. The PCA revealed a four-factor solution: “pure impulsivity,” “planning and thinking,” “lack of attention and concentration,” and “impulsive buying.” A significant effect of sex and years of education was found. Norms for the adjustment of raw scores were provided (cutoff = 37.39). Conclusions: The BIS-15 showed almost identical psychometric properties as compared with the original scale, reducing the administration time. Our norms may allow identifying individuals with impulsivity of clinical interest