The Factor Structure of the Italian version of the MCMI-III compared to the Dutch and American versions.

Introduction: Previously factor analytic research on the Millon Clinical Multiaxial Inventory-III (MCMI-III) using different factor extraction procedures, found three or four factors. In particular, Rossi, van der Ark, and Sloore (2007), through a sophisticated research design that examined and compared various aspects of the factor structure of the MCMI-III, identified a four-factor solutions for both male and female subsamples and for both linearly dependent and independent scales. The aim of this study was to explore the factor structure of the Italian version of the MCMI-III using both linearly dependent and independent scales, to evaluate gender differences, and to compare our results with the Dutch and American factor structure. Method: The present study used a sample of 881 psychiatric patients of Northern and Central Italy. Principal Factor Analysis with direct oblimin rotation was performed for the entire sample and for both men and women. Results: We identified four factors that were similar for men and women, but we found differences in content between solutions with overlapping and non-overlapping scale. The four-factor solution was similar to the Dutch one and the first two factors were congruent with the three-factor solution proposed in American studies. Conclusions: Taken together, our findings indicate that the factor structure of the MCMI-III is consistent across countries.