A comparative study of the dimensions and facets of the five-factor model in the diagnosis of cases of personality disorder.

Two national samples of psychologists (n = 92, n = 89) rated personality disorder cases using either the five factors (domains) or the 30 facets of the five-factor model (FFM) to examine reliability and clinical utility of the model when used as a diagnostic tool. The cases were prototypic and nonprototypic cases representing the three clusters of personality disorders in the DSM-IV. Although confidence was higher using the factors rather than the facets to rate the cases, interrater reliability was similar and the facets were rated more useful for professional communication, case conceptualization, and treatment. Mean ratings for the prototypic cases supported the theorized relationships between those personality disorders and the FFM. Principal components factor analysis of the facet ratings largely replicated the structure of the FFM with only a few facets failing to load with their superordinate dimension in the model. Implications for use of the FFM with personality disorder are discussed.