OBJECTIVES: Relatively few systematic data exist on the clinical impact of bipolar comorbidity in obsessive-compulsive disorder (OCD) and no studies have investigated the influence of such a comorbidity on the prevalence and pattern of Axis II comorbidity. The aim of the present study was to explore the comorbidity of personality disorders in a group of patients with OCD and comorbid bipolar disorder (BD). METHODS: The sample consisted of 204 subjects with a principal diagnosis of OCD (DSM-IV) and a Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score>or=16 recruited from all patients consecutively referred to the Anxiety and Mood Disorders Unit, Department of Neuroscience, University of Turin over a period of 5 years (January 1998-December 2002). Diagnostic evaluation and Axis I comorbidities were collected by means of the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I). Personality status was assessed by using the Structured Clinical Interview for DSM-IV Axis II Disorders (SCID-II). Socio-demographic and clinical features (including Axis II comorbidities) were compared between OCD patients with and without a lifetime comorbidity of BD. RESULTS: A total of 21 patients with OCD (10.3%) met DSM-IV criteria for a lifetime BD diagnosis: 4 (2.0%) with BD type I and 17 (8.3%) with BD type II. Those without a BD diagnosis showed significantly higher rates of male gender, sexual and hoarding obsessions, repeating compulsions and lifetime comorbid substance use disorders, when compared with patients with BD/OCD. With regard to personality disorders, those with BD/OCD showed higher prevalence rates of Cluster A (42.9% versus 21.3%; p=0.027) and Cluster B (57.1% versus 29.0%; p=0.009) personality disorders. Narcissistic and antisocial personality disorders were more frequent in BD/OCD. CONCLUSIONS: Our results point towards clinically relevant effects of comorbid BD on the personality profiles of OCD patients, with higher rates of narcissistic and antisocial personality disorders in BD/OCD patients.
