Axis I and II comorbidity in a large sample of patients with obsessive–compulsive disorder

Background: No study has reported yet on the prevalence of both comorbid DSM-IV axis I and personality disorders in a large cohort of OCD patients, and little is known about differences in clinical characteristics between OCD patients with and without comorbid symptoms. Objective: To examine the cross-sectional prevalence of comorbid DSM-IV axis I, and personality disorders in a population of patients with primary obsessive–compulsive disorder (OCD). Method: 420 outpatients with OCD were evaluated for comorbid pathology, demographic, and clinical characteristics. Results: Forty-six percent of the patients were diagnosed with a comorbid disorder. Twenty-seven percent met the criteria for at least one comorbid axis I disorder, 15.6 percent for a comorbid personality disorder, and 20.4 percent for both a comorbid axis I disorder and a personality disorder. Limitations: A limitation of the current study is that the sample was drawn from a psychiatric department specialised in anxiety disorders, which might have underestimated the rate of comorbid diagnoses. Conclusion: Comorbid diagnoses occur less frequently than would be expected on the basis of comparable comorbidity studies in OCD. Associated axis I comorbidity did not affect clinical severity of OCD, but was related to higher levels of depression and anxiety, whereas axis II comorbidity impaired to a higher extent the overall functioning.