Item Response Theory Analyses, Factor Structure, and External Correlates of the Italian Translation of the Personality Inventory for DSM-5 Short Form in Community-Dwelling Adults and Clinical Adults.

To assess the psychometric properties of the Italian translation of the 100-item short form of the Personality Inventory for DSM-5 (PID-5-SF), 2,143 community-dwelling adults (59.6% female), and 706 adult clinical participants (52.4% female) were administered the Italian translation of the PID-5. Clinical participants were also administered the Structured Clinical Interview for DSM-IV (SCID-II), and the Personality Diagnostic Questionnaire-4+ (PDQ-4+). Item response theory analysis showed that all proposed PID-5-SF items showed adequate item discrimination parameters in both community-dwelling adults and clinical adults. All PID-5-SF trait scales showed satisfactory internal consistency estimates. PID-5-SF five-factor structure closely matched the factor structure of the PID-5 in both community-dwelling participants and clinical participants and was invariant across the two samples that participated in this study. Moreover, the factor structure of the PID-5-SF closely replicated the factor of the PID-5-SF that was originally reported in Maples et al.'s study. In our clinical sample, dominance analysis results showed that PID-5-SF scales explained a nonnegligible and significant amount of variance in both SCID-II and PDQ-4+ ratings of selected DSM-5 Section II personality disorder, and the use of the PID-5-SF did not result in a substantial loss of information as compared with the original PID-5.