Reliability and validity of the Personality Disorder Severity ICD-11 (PDS-ICD-11) scale and the Revised Personality Assessment Questionnaire for ICD-11 (PAQ-11R) in a Norwegian community sample

In the ICD-11, a new model for the diagnosis of personality disorders is included, consisting of an assessment of the severity of personality impairment as well as an optional evaluation of pathological personality traits. This study aimed to examine the reliability, structural validity, and convergent and discriminant validity of the Norwegian versions of the Personality Disorder Severity ICD-11 (PDS-ICD-11) scale for the assessment of personality disorder severity and the Revised Personality Assessment Questionnaire for ICD-11 (PAQ-11R) for the assessment of the ICD-11 pathological personality traits in a Norwegian community sample. The sample consisted of 295 participants (75.9% female) with a mean age of 30.0 years (SD = 10.7 years). The participants answered the PDS-ICD-11, PAQ-11R, Level of Personality Functioning Scale-Brief Form 2.0 (LPFS-BF 2.0), and the Personality Inventory for DSM-5-Brief Form Plus Modified (PID5BF + M). The Norwegian PDS-ICD-11 showed good reliability. Support for a unidimensional model and a high convergent correlation with the LPFS-BF 2.0 was found. The reliability analysis of the Norwegian PAQ-11R scales yielded mixed findings with suboptimal reliability estimates for the PAQ-11R detachment, disinhibition, and dissociality scales. Analyzing the structure of the PAQ-11R items, four factors emerged (negative affectivity, detachment, disinhibition, and anankastia). The PAQ-11R scales showed good convergent and, overall, adequate discriminant validity with the PID5BF + M scales. The findings support the use of the PDS-ICD-11 for assessing severity in the ICD-11 PD model in Norway. The Norwegian PAQ-11R appears to be a useful screening tool for the ICD-11 PD trait domains.