Obsessive-compulsive disorder and the five-factor model of personality: distinction and overlap with major depressive disorder.

Research on individual differences in obsessive-compulsive disorder (OCD) has focused largely on analogue models with participants experiencing sub-clinical obsessions and/or compulsions. Few studies have examined the association between normal, dimensional personality traits and obsessive-compulsive symptomatology in a clinical sample. The purpose of this study was to examine personality differences in patients with a primary diagnosis of OCD (n = 98) or major depression (n = 98) using the domains and facets of the five-factor model of personality (FFM). Patients completed the self-report version of the Revised NEO Personality Inventory (NEO PI-R). When contrasted with community controls (Revised NEO Personality Inventory (NEO-PI-R) and NEO Five-Factor Inventory (NEO-FFI) professional manual, Psychological Assessment Resources, Odessa, FL, 1992), participants with OCD were found to differ across the domains (and facets) of neuroticism, extraversion, and conscientiousness and the facets of openness and agreeableness. Further, when compared to depressed participants, those with OCD were found to be more extraverted, agreeable, conscientious and less neurotic. With the exception of the conscientiousness domain (and facets), these significant differences were maintained even after controlling for depression severity. These results highlight the unique associations between trait domains and facets of the FFM and OCD.