Screening for Personality Disorders Using the Level of Personality Functioning: Diagnostic Accuracy of the LPFS-BF 2.0 in Clinical and <i>Sine Morbo</i> Samples

The current study aimed to determine cutoff scores of the Level of Personality Functioning Scale-Brief Form 2.0 (LPFS-BF 2.0) in clinical and nonclinical samples and thereby test its ability to discriminate between those samples. A total of 814 individuals participated, including a <i>sine morbo</i> (SM; Latin for "without any disease"; here specifically "without any mental disorder") subsample (<i>n</i> = 509), a clinical subsample without personality disorder (non-PD; <i>n</i> = 240), and a clinical subsample with personality disorder (PD; <i>n</i> = 65). Significant differences were found among the subsamples on all LPFS-BF 2.0 scores, with the PD subsample showing the most severe impairments, followed by the non-PD and SM subsamples. To determine cutoff scores, ROC curve analyses were conducted on 70% of the data (training set, randomly selected) and validated on the remaining set of the data (test set), controlling for age, sex, and level of education. The accuracy of the LPFS-BF 2.0 in discriminating between all three subsamples was demonstrated.