RESUMO
The Self and Interpersonal Functioning Scale (SIFS) is a 24-item self-report questionnaire assessing personality functioning according to the alternative DSM-5 model for personality disorders. We evaluated the German SIFS version in a total sample of 886 participants from Germany and Switzerland. Its factor structure was investigated with confirmatory factor analysis comparing bifactor models with two specific factors (self- and interpersonal functioning) and four specific factors (identity, self-direction, empathy, and intimacy). The SIFS sum and domain scores were tested for reliability and convergent validity with self-report questionnaires and interviews for personality functioning, -organization, -traits, -disorder categories, and well-being. None of the bifactor models yielded good model fit, even after excluding two items with low factor loadings and including a method factor for reverse-keyed items. Based on a shortened 22-item SIFS version, models suggested that the g-factor explained 52.9-59.6% of the common variance and that the SIFS sum score measured the g-factor with a reliability of .68-.81. Even though the SIFS sum score showed large test-retest reliability and correlated strongly with well-established self-report questionnaires and interviews, the lack of structural validity appears to be a serious disadvantage of the SIFS compared to existing self-reports questionnaires of personality functioning.
RESUMO
OBJECTIVE: Difficulties in the assessments of Somatoform Disorders (SD) and Personality Disorders (PD) regarding operationalization, arbitrary thresholds, and reliability led to a shift from categorical to dimensional models in the DSM-5. Empirical research data postulates a continuous level of severity in both groups of diseases. The aim of this systematic review was to investigate the overlap between somatization and personality pathology. METHODS: Until July 2020, we conducted a systematic literature search with PubMed, Web of Science and SCOPUS. We specifically reviewed current empirical data on the Alternative Model of Personality Disorders (AMPD) and Somatic Symptom Disorder (SSD) and SD. Data was drawn out using predefined data panels. Results were reflected in the context of the Hierarchical Taxonomy of Psychopathology (HiTOP) model. Risk of bias was assessed due to blinding, randomization, selective reporting, incomplete data, and attribution bias. RESULTS: A total of eight studies (N = 2979) met the inclusion criteria. Whereas categorical measures revealed mixed results, positive correlations between SD/SSD and dimensionally measured personality functioning were present in four studies (N = 1741). In three studies (N = 2025) correlations between SD/SSD and neuroticism/negative affectivity (d = 0.22-1.041) were present. Moreover, harm avoidant (d = 0.526 - 0.826) and self-defeating traits (d = 0.892) revealed significant associations with somatization. CONCLUSIONS: Dimensional personality assessments are highly neglected in patients with SSD and warrant further research. However, in line with the HiTOP model, there is tentative evidence that somatization can be described as an independent personality trait, which shows most striking overlaps with self-pathologies (Criterion A) and the trait of negative affectivity (Criterion B).
