Further Evidence for the Validity of a Response Inconsistency Scale for the Personality Inventory for DSM-5 in Italian Community-Dwelling Adolescents, Community-Dwelling Adults, and Clinical Adults

Response inconsistency represents a major component of careless responding. Keeley, J. W., Webb, Peterson, Roussin, and Flanagan (2016) proposed a measure of response inconsistency for the Personality Inventory for DSM-5 (PID-5-VRIN). In order to evaluate the ability of the PID-5-VRIN scale to detect inconsistent responding, we examined 3 independent archival samples of Italian community-dwelling adolescents (N = 1,264), community-dwelling adults (N = 2,143), and clinical adults (N = 706) who were administered the PID-5. The impact of PID-5-VRIN scores on the associations with interview-based personality disorder (PD) scores was also assessed among clinical adults. PID-5-VRIN item pairs showed correlational values of at least medium size by conventional standards. Moreover, the PID-5-VRIN seemed to be efficient in discriminating real data from random responses in all samples. In line with Keeley and colleagues' findings, a PID-5-VRIN total score of 17 represented the best balance between sensitivity and specificity in all samples. Clinical adult participants who met this threshold for invalidity also obtained significantly higher scores on the majority of PID-5 trait scales. When the correlations between selected PID-5 trait scale scores and the corresponding interview-based ratings of DSM-5 Section II PDs were considered, appreciable differences in the magnitude and/ or direction of association were observed between participants scoring below the PID-5-VRIN cutoff and those meeting the threshold for invalidity (>= 17). As a whole, our data suggest that the PID-5-VRIN represents an efficient means of assessing inconsistent responding on the PID-5.