Two-year retest reliability and predictive validity of the Self- and Informant-Personality Inventory for ICD-11 in older adults.

Abstract

The International Classification of Diseases, 11th edition (ICD-11) adopted a fully dimensional model of personality disorder. The Personality Inventory for ICD-11 (PiCD) and Informant-Personality Inventory for ICD-11 (IPiC) were developed to assess the ICD-11 trait model, and the PiCD has since received significant validation support. However, there has only been one prior study of longitudinal predictive validity of the PiCD, two relatively short test-retest reliability studies of the PiCD, and no prior longitudinal tests of the IPiC. Longitudinal psychometric support for psychological assessment measures is essential. The present study provides a longer, larger, 2-year psychometric validation test of the PiCD and IPiC. Participants (N = 711) and their informants (N = 569) were recruited in the St. Louis Personality and Aging Network. The results demonstrated strong 2-year retest reliability for the PiCD and IPiC, as well as mean-level stability. Additionally, we explored the relationships between the PiCD and IPiC and important life outcome measures (depressive symptoms, satisfaction with life, and health status). The analysis revealed several significant associations between PiCD and IPiC scales and the outcome variables across time. Further, the PiCD Negative Affectivity and IPiC Detachment scales demonstrated incremental validity over each other and the outcome variables at Wave 1 in the prediction of depressive symptoms and satisfaction with life, respectively. The findings provide essential longitudinal test-retest reliability and predictive validity support for the PiCD and IPiC. Public Significance StatementThis 2-year study on the Personality Inventory for ICD-11 (PiCD) and Informant-Personality Inventory for ICD-11 (IPiC) highlights robust retest reliability for both scales in a sample of older community adults. Evidence is also found for mean-level stability and associations between the scales and depressive symptoms, satisfaction with life, and health status. This research provides essential, foundational longitudinal psychometric support for both the PiCD and IPiC scales.