Level of Personality Functioning in Turkish Clinical and Community Samples: Validation of the LPFS-SR-TR and Its...

This study examines the validity and reliability of the Turkish version of the Level of Personality Functioning Scale-Self-Report (LPFS-SR-TR) and its associations with personality disorder (PD) categories and Axis I comorbidities. The cross-sectional study included 720 participants aged 18-65. From a consecutive sample of 732 patients who presented to the outpatient psychiatry clinic, experienced psychiatrists suspected 207 of having PD. They were further diagnosed using the structured clinical interview for DSM-III-R personality disorders (SCID-II). Patients were also investigated for Axis I disorders using the SCID-5 clinical version. A community-based control group of 513 participants recruited through convenience sampling received self-assessment-based SCID-II without a clinical interview. Both groups underwent the Big Five Inventory (BFI) and LPFS-SR-TR. The six-factor model provided the best statistical fit. Significant correlations between the LPFS-SR-TR and BFI indicate concurrent validity. Patients scored higher on the LPFS-SR-TR. Using a total score threshold of greater than 277.5 resulted in 93.2% sensitivity and 83.0% specificity (AUC = 0.94) for identifying PDs, indicating discriminant validity. Serial logistic models suggested incremental validity. The scale demonstrated strong internal consistency (Cronbach's α = 0.96) and test-retest reliability (ICC = 0.86). The LPFS-SR-TR is valid and reliable for assessing the presence and severity of PDs. The hypothesized one-dimensional factor structure may be supported given its ability to distinguish PDs from a community sample. Axis I comorbidities are common and diverse without any discernible pattern.