Level of Personality Functioning in Turkish Clinical and Community Samples: Validation of the LPFS‐SR‐TR and Its Associations With Axis I Disorders

ABSTRACT 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.