Revision of a Measure of Personality Impairment for the International Classification of Diseases, 11th Edition (ICD-11)

The two major classification systems of mental health disorders, the International Classification of Diseases (ICD) and Diagnostic and Statistical Manual of Mental Disorders (DSM), have moved away from categorical models of personality disorder (PD) and toward dimensional ones in their most recent editions. A core similarity between the most recent DSM and ICD PD models is that they both require evidence of personality functioning impairment for diagnosis. A fairly large literature examining the construct validity of DSM-5, Section III’s (DSM-5-III) conceptualization of personality dysfunction has developed in recent years. A key factor facilitating the development of this literature is the existence of several, primarily self-report, measures created explicitly based on DSM-5-III’s Criterion A—personality functioning impairment. In contrast, the literature on ICD‑11’s conceptualization of personality impairment is much more limited. This is due, in part, to the lack of measures explicitly targeting this component of the ICD-11 PD model, largely because its recent (May 2019) approval was of only its “statistical” version, with the fuller descriptions of the Clinical Description and Diagnostic Guidelines not yet fully publicly available. The current manuscript builds on the only existing comprehensive measure of ICD-11 personality impairment (Clark et al., 2021) by re-analyzing the item pool from which it was derived and developing a revised measure prioritizing discriminant validity in relation to ICD-11 maladaptive traits. The psychometric properties of the revised measure, as well as certain aspects of its nomological network (e.g., associations with external personality trait measures) are discussed. Thus, the present study contributes to the literature by introducing a revised self-report measure of ICD-11 personality functioning impairment for use in future research evaluating the ICD-11 PD model and the personality functioning impairment construct more generally.