Personality Disorders: Theory, Research, and Treatment, Vol 17(1), Jan 2026, 42-52; doi:10.1037/per0000748
The Level of Personality Functioning Scale-Brief Form 2.0 (LPFS-BF 2.0) is a brief measure for personality functioning based on the Alternative Model for Personality Disorders. Despite a strong emerging research base in support of the measure, most studies have been conducted in North America or Europe, and few studies have explored its association with theoretically relevant correlates such as mentalizing and attachment. The current study examined its factor structure, reliability, measurement invariance, and validity in Iranian samples using Exploratory Structural Equation Modeling. Two Iranian samples participated, composed of community-dwelling adults (N = 579, 58.9% female, Mage = 33.47) and university students (N = 390, 70.8% female, Mage = 27.09). Participants completed the LPFS-BF 2.0 alongside measures of categorical personality pathology, mentalizing, and attachment. Competing measurement models were contrasted, and invariance was tested across samples, sexes, age groups, and diagnostic status. A two-factor Exploratory Structural Equation Modeling model representing self and interpersonal functioning demonstrated optimal fit with good reliability and measurement invariance across all groups. Both domains showed strong associations with attachment insecurities, mentalizing deficits, and personality pathology. The mean score of self dysfunction was significantly higher in students, females, emerging adults, and diagnosed participants, while the interpersonal domain showed no significant group differences. The LPFS-BF 2.0 showed robust psychometric properties in Iranian samples, supporting its cross-cultural utility. Given that self dysfunction varied significantly by sample type, sex, age, and diagnostic status while interpersonal dysfunction did not, the self domain appears to better distinguish between demographic and clinical groups. (PsycInfo Database Record (c) 2026 APA, all rights reserved)