Quetiapine for Bipolar Depressive Episode in Obsessive-Compulsive Disorder Patients Maintained on Selective Serotonin Reuptake Inhibitor Treatment

Objectives A meaningful proportion of patients with obsessive-compulsive disorder (OCD) develop symptoms of bipolar depression (BP-D). In the present investigation, we aimed to determine whether quetiapine is efficacious in OCD patients who despite continuous treatment with a selective serotonin reuptake inhibitor developed an acute episode of BP-D. Methods We analyzed 68 charts of Diagnostic and Statistical Manual of Mental Disorders Fifth Edition OCD patients from our outpatient clinic and identified 15 patients who in addition met Diagnostic and Statistical Manual of Mental Disorders Fifth Edition criteria for bipolar II disorder, depressive episode. Eleven (7 men and 4 women, aged 24-54 years) patients for whom quetiapine was added to treat the index episode of BP-D were included. Treatment response was assessed retrospectively and defined as a score of "much improved" or "very much improved" on the Clinical Global Impression-Improvement scale. Results Quetiapine was added for treatment of BP-D in a dose range of 150 to 400 mg (mean, 273 mg). Eight (73%) of the 11 study patients fulfilled the criterion of response, that is a score of "much improve" (4 patients) and "very much improved" (4 patients) on the Clinical Global Impression-Improvement scale. Notably, quetiapine was associated with additional improvement of OCD symptoms in 6 of 8 study responders. Quetiapine was well tolerated. The most frequently detected side effects were drowsiness (5 patients), constipation (4 patients), and orthostatic hypotension (2 patients). Conclusions The revealed beneficial effect of quetiapine addition for acute episode of BP-D in OCD patients maintained on selective serotonin reuptake inhibitor treatment merits further controlled investigation.