Background: While numerous studies have documented the high comorbidity of major depressive disorder (MDD) with individual mental disorders, no published study has reported overall current comorbidity with all Axis I and II disorders among psychiatric patients with MDD, nor systematically investigated variations in current comorbidity by sociodemographic factors, inpatient versus outpatient status, and number of lifetime depressive episodes.
Method: Psychiatric outpatients and inpatients in Vantaa, Finland, were prospectively screened for an episode of DSM-IV MDD, and 269 patients with a new episode of MDD were enrolled in the Vantaa Depression MDD Cohort Study. Axis I and II comorbidity was assessed via semistructured Schedules for Clinical Assessment in Neuropsychiatry, version 2.0, and Structured Clinical Interview for DSM-II-R personality disorders interviews.
Results: The great majority (79%) of patients with MDD suffered from 1 or more current comorbid mental disorders, including anxiety disorder (57%), alcohol use disorder (25%), and personality disorder (44%). Several anxiety disorders were associated with specific Axis II clusters, and panic disorder with agoraphobia was associated with inpatient status. The prevalence of personality disorders varied with inpatient versus outpatient status, number of lifetime depressive episodes, and type of residential area, and the prevalence of substance use disorders varied with gender and inpatient versus outpatient status.
Conclusion: Most psychiatric patients with MDD have at least 1 current comorbid disorder. Comorbid disorders are associated not only with other comorbid disorders, but also with sociodemographic factors, inpatient versus outpatient status, and lifetime number of depressive episodes. The influence of these variations on current comorbidity patterns among MDD patients needs to be taken account of in treatment facilities.