Depressive Personality Disorder BAGBY ET AL. DEPRESSIVE PERSONALITY DISORDER: RATES OF COMORBIDITY WITH PERSONALITY DISORDERS AND RELATIONS TO THE FIVE–FACTOR MODEL OF PERSONALITY R. Michael Bagby, PhD, Deborah R. Schuller, MD, Margarita B. Marshall, BSc, and Andrew G. Ryder, PhD Depressive personality disorder (DPD) is listed in the DSM–IV as one of the “Disorders for Further Study.” In this investigation we examined (1) the rates of comorbidity of DPD with the 10 personality disorders (PDs) in the main text of DSM–IV, and (2) the convergent and discriminant validity of DPD in its relation to the 30 facet traits of the Five–Factor Model of per- sonality (FFM). One hundred and sixty–nine participants with psychiat- ric diagnoses were interviewed with the Structured Clinical Interview for DSM–IV Personality Disorders Questionnaire (SCID–II) and completed the Revised NEO Personality Inventory (NEO PI–R). A total of 26 (15%) of the participants met diagnostic criteria for at least one of the 10 main text PDs, and 15 (9%) met criteria for DPD. Of those who met criteria for DPD, 10 (59%) of the participants also met criteria for one or more of the 10 main text PDs. Regression analyses indicated a four–facet trait set de- rived from the NEO PI–R thought to be uniquely associated with DPD ac- counted for a significant amount of variance in DPD SCID–II PD scores and was significantly larger for DPD than it was for the 9 of the 10 main text PDs; the sole exception was for avoidant PD. Diagnostically, DPD overlaps significantly with other PDs but is distinguishable in its unique relation with traits from the FFM. Depressive personality disorder (DPD) has been the focus of ongoing debate and empirical investigation addressing its viability for inclusion in future editions of the DSM (Bagby, Ryder, & Schuller, 2003; Huprich, 2001a; McDermut, Zimmerman, & Chelminski, 2003; Ryder, Bagby, & Schuller, 2002). One area of controversy centers on the convergent and discriminant 542 Journal of Personality Disorders, 18(6), 542-554, 2004 © 2004 The Guilford Press From the Centre for Addiction and Mental Health, and Department of Psychiatry, University of Toronto (R.M.B., D.R.S.), the Department of Psychology, McGill University in Montreal (M.B.M.), and the Department of Psychology, Concordia University in Montreal (A.G.R.). Preparation of this paper was facilitated by an Ontario Mental Health Foundation Senior Re- search Fellowship awarded to the first author. Margarita B. Marshall is now at Department of Psychology, McGill University, Montréal, Canada. Andrew G. Ryder is now at Department of Psychology, Concordia University, Montréal, Canada. Address correspondence to Dr. R. Michael Bagby, Section on Personality and Psychopathology, Centre for Addiction and Mental Health, Clarke Site, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; E–mail: michael_bagby@camh.net