Obsessive-Compulsive-Bipolar Comorbidity: A Systematic Exploration of Clinical Features and Treatment Outcome

Background: Notwithstanding the emerging literature on comorbidity between obsessive-compulsive disorder (OCD) and bipolar disorder, relatively few systematic data exist on the clinical characteristics of this interface and its treatment. The aim of the present study is to address this challenge as it appears in a setting of routine clinical practice.

Method: The sample comprised 68 patients with comorbid DSM-IV diagnoses of OCD and major depressive episode admitted and treated at the day-hospital in the Department of Psychiatry at the University of Pisa (Pisa, Italy) during a 3-year period (January 1995-December 1998). Thirty-eight patients (55.8%) showed lifetime comorbid bipolar disorder (12 [31.6%] bipolar I and 26 [68.4%] bipolar II). Diagnoses and clinical features were collected by means of structured (Structured Clinical Interview for DSM-IV) and semistructured interviews (OCD-Interview). Assessments of drug treatments, clinical outcome, and adverse effects were made prospectively as part of routine clinical care throughout the course of their day-hospitalization.

Results: In contrast with non-bipolar OCD patients, OCD-bipolar patients showed a more episodic course with a greater number of concurrent major depressive episodes. They reported a significantly higher rate of sexual obsessions and significantly lower rate of ordering rituals. Furthermore, they reported more frequent current comorbidity with panic disorder-agoraphobia and abuse of different substances (alcohol, sedatives, nicotine, and coffee). Drug treatment with clomipramine and, to a lesser extent, with selective serotonin reuptake inhibitors was associated with hypomanic switches in OCD-bipolar patients, especially in those not concomitantly treated with mood stabilizers. A combination of multiple mood stabilizers was necessary in 16 OCD-bipolar patients (42.1%) and a combination of mood stabilizers with atypical antipsychotics was required in 4 cases (10.5%). OCD-bipolar patients tended to show a less positive outcome for mood symptomatology and general functioning. Three patients required hospitalization for severe mixed episode.

Conclusion: In a tertiary care center, comorbidity between OCD and bipolar disorder is a significant clinical problem affecting a large number of patients and has a substantial impact on the clinical characteristics and treatment outcome of both disorders.