Co-morbid obsessive-compulsive disorder (OCD) in bipolar disorder (BD) negatively affects clinical course and outcome, and considerably complicates its treatment.

To show a therapeutic approach still rarely used in case of resistant bipolar disorder associated with OCD.

Presentation of the clinical case of Mr. M.H., who is treated in our department since 2008 for OCD-bipolar co-morbidity, followed by a literature review.

Mr. M.H. is a 29-year-old male patient. He developed BD associated to OCD at age 20. In order to control bipolar symptoms, the patient received several trials of anti-psychotics combined with mood stabilizers with little improvement. Resistant BD was diagnosed, and clozapine 300 mg daily introduced, leading to significant improvement in bipolar symptoms but worsening in OC symptoms. Treatment of OCD with fluoxetine and with cognitive-behavioral therapy (CBT) was unsuccessful. Introduction of aripiprazole 20 mg daily led to decided improvement of OC-symptoms. After one year, clozapine was gradually tapered down to 150 mg daily without reappearance of bipolar symptoms but further improvement of OC-symptoms.

Treatment of OCD-bipolar co-morbidity is difficult given the risk of manic switch with antidepressants and the risk of benzodiazepine dependence. CBT could represent an alternative, however, it did not show any efficacy in our patient. Worsening of OCD under clozapine is described in the literature. Adjunction of aripiprazole to clozapine seems an interesting therapeutic option: it diminishes OC symptoms without destabilizing the patient's mood state.

The authors have not supplied their declaration of competing interest.