A DSM-5 AMPD and ICD-11 compatible measure for an early identification of personality disorders in adolescence–LoPF-Q 12–18 latent structure and short form

• Published in: PloS one 2022-09, Vol.17 (9), p.e0269327-e0269327
• Main Authors: Zimmermann, Ronan, Steppan, Martin, Zimmermann, Johannes, Oeltjen, Lara, Birkhölzer, Marc, Schmeck, Klaus, Goth, Kirstin
• Format: Article
• Language: English
• Subjects: Adolescence; Adolescents; Algorithms; Ant colony optimization; Biology and Life Sciences; Child development; Demographic aspects; Diagnosis; Empathy; Factor analysis; Intimacy; Latent class analysis; Medical diagnosis; Medical examination; Medicine and Health Sciences; Mental disorders; Modelling; Optimization; Patients; People and Places; Personality; Personality disorders; Personality tests; Personality traits; Physical Sciences; Psychological aspects; Quantitative psychology; Questionnaires; Research and Analysis Methods; Social Sciences; Teenagers; Validity; Youth
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0269327

The LoPF-Q 12–18 (Levels of Personality Functioning Questionnaire) was designed for clinical use and to promote early detection of personality disorder (PD). It is a self-report measure with 97 items to assess personality functioning in adolescents from 12 years up. It operationalizes the dimensional concept of personality disorder (PD) severity used in the Alternative DSM-5 Model for Personality Disorders and the ICD-11. In this study, we investigated the factorial structure of the LoPF-Q 12–18. Additionally, a short version was developed to meet the need of efficient screening for PD in clinical and research applications. To investigate the factorial structure, several confirmatory factor analysis models were compared. A bifactor model with a strong general factor and four specific factors showed the best nominal fit (CFI = .91, RMSEA = .04, SRMR = .07). The short version was derived using the ant colony optimization algorithm. This procedure resulted in a 20-item version with excellent fit for a hierarchical model with four first order factors to represent the domains and a secondary higher order factor to represent personality functioning (CFI = .98, RMSEA = .05, SRMR = .04). Clinical validity (effect size d = 3.1 between PD patients and controls) and clinical utility (cutoff ≥ 36 providing 87.5% specificity and 80.2% sensitivity) for detecting patients with PD were high for the short version. Both, the long and short LoPF-Q 12–18 version are ready to be used for research and diagnostic purposes.