Intolerance of Uncertainty Scale (IUS-27 e IUS-12): due studi preliminari

Intolerance of uncertainty refers to a set of negative beliefs about uncertainty and its consequences; it is thought to play a key role in the development and maintenance of pathological worry, but its transdiagnostic nature has been recently demonstrated. The Intolerance of Uncertainty Scale (IUS) represents the main instrument designed to measure this construct; two separated components, namely «prospective intolerance of uncertainty» and «inhibitory intolerance of uncertainty», have been identified. Furthermore, recent evidence suggests that the newly developed reduced and revised version of the scale (IUS-12) is characterised by a greater number of strengths than the original one (IUS-27). The aim of this research was to preliminary test the goodness of the IUS in the Italian context through the conduction of two studies. In Study 1, 244 community individuals were administered the IUS-27; results from exploratory factor analysis revealed that the questionnaire was a reliable measure made up of two factors; nonetheless, these two dimensions did not reflect clearly distinguishable facets of intolerance of uncertainty. Consequently, Study 2 was performed to assess the factor structure and the psychometric properties of the IUS-12 in a sample composed of 208 university students. Confirmatory factor analyses showed that the two-factor model had a better fit to data that the one-factor model. Furthermore, the IUS-12 demonstrated good internal consistency values, gender invariance, and adequate construct and discriminant validities. Further studies investigating the factor structure and the psychometric properties of the scale in both community and clinical Italian samples are necessary.