Validity of an Inconsistency Scale for the PID-5 in Community-Dwelling Younger and Older Adults

Abstract: The Personality Inventory for DSM-5 (PID-5; Krueger et al., 2012) is a self-report questionnaire measuring pathological traits of personality disorders. Keeley and colleagues (2016) developed an Inconsistency Scale for the PID-5 (PID-5-INC) to detect random responses. We examined the ability of the PID-5-INC to detect inconsistent responders in a new linguistic context (Dutch) and age group (older adults). The Dutch PID-5 version (van der Heijden et al., 2014) was administered to two Dutch community-dwelling younger (18-64 years old: N = 439) and older adults (65 years or older: N = 251). The PID-5-INC item pairs showed large interitem correlations in the younger adult sample and at least medium interitem correlations, except for one item pair, in the older adult sample. Similarly to Keeley and colleagues, a cut-off score of 17 was the optimal cut-off point for both the younger and older adult samples. However, for the younger adult sample, a cut-off score of 16 provided an even better balance between specificity and sensitivity. We concluded that our results support the use of the PID-5-INC in Dutch-speaking community-dwelling younger and older adults and point out the importance of including validity scales for self-report questionnaires.