Objective: This article examined, using theories from cognitive science, the clinical utility of the Five-Factor Model (FFM) of Personality, an assessment and classification system under consideration for integration into the forthcoming fifth edition of the Diagnostic and Statistical Manual (DSM) of Mental Disorders. Specifically, the authors sought to test whether FFM descriptors are specific enough to allow practicing clinicians to capture core features of personality disorders.

Method: In two studies, a large nationwide sample of clinical psychologists, psychiatrists, and clinical social workers (N = 187 and N = 191) were presented case profiles based on symptom formats from either the DSM-IV and/or FFM. Ratings for six aspects of clinical utility for DSM-IV and FFM profiles were obtained and participants provided DSM-IV diagnoses. Prototypic cases (only one personality disorder) and comorbid cases were tested in separate studies.

Results: Participants rated the DSM-IV as more clinically useful than the FFM on five out of six clinical utility questions. Despite demonstrating considerable background knowledge of DSM-IV diagnoses, participants had difficulty identifying correct diagnoses from FFM profiles.

Conclusion: The FFM descriptors may be more ambiguous than the criteria of the DSM-IV and the FFM may therefore be less able to convey important clinical details than the DSM-IV. The findings flag challenges to clinical utility for dimensional trait systems such as the FFM.