Intolerance of Uncertainty Scale (IUS-27 and IUS-12): Two preliminary studies
Gioia Bottesi, Marta Ghisi, Caterina Novara, Jessica Bertocchi, Marco Boido, Ilaria De Dominicis, Mark Freeston
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.
Keywords
Intolerance of uncertainty, Questionnaire, Factor structure, Psychometric properties.
