Incremental validity of the ICD-11 personality disorder model for explaining psychological distress

Many persons with personality disorder experience psychological distress. The International Classification of Diseases, 11th Revision (ICD-11) contains a dimensional personality disorder model that comprises personality dysfunctioning, 5 maladaptive personality trait domains, and a borderline pattern qualifier. Research on the relations between the ICD-11 personality disorder model and psychological distress is sparse. Particularly, it is unclear whether personality dysfunctioning on the one side and the more specific personality traits in ICD-11 on the other side incrementally predict psychological distress. In addition, the incremental validity of the components of the ICD-11 personality disorder model beyond the five-factor model of normal-range personality as a widely accepted personality framework has not been established. In this study, we assessed the relations between self-report measures of the ICD-11 personality disorder model and psychological distress in 2 community samples (N_{Sample 1} = 203, N_{Sample 2} = 226). Except anankastia, all ICD-11 personality trait domains assessed with the Personality Inventory for ICD-11 and the borderline pattern qualifier assessed with the Borderline Pattern Scale were strongly related to psychological distress. In hierarchical regressions, the personality traits in ICD-11 incrementally predicted psychological distress beyond personality dysfunctioning, and vice versa. In addition, the components of the ICD-11 personality disorder model were substantially related to psychological distress beyond the corresponding normal-range Big Five personality traits. Our results demonstrate the criterion-related and incremental validity of self-report instruments assessing the ICD-11 personality disorder model, which supports their utility for screening and assessment. (PsycInfo Database Record (c) 2022 APA, all rights reserved).