Depression frequently occurs in the setting of cardiovascular disease, including atrial fibrillation. Anticoagulants such as warfarin are commonly used in patients with atrial fibrillation in order to prevent the occurrence of stroke, while selective serotonin reuptake inhibitors (SSRIs), the mainstays of antidepressant pharmacology, have been associated with abnormal coagulation and have been reported to cause bleeding. This effect of the SSRIs may be secondary to their impairment of platelet aggregation and/or their inhibitory effects on cytochrome P‐450 enzymes, including those involved in the elimination of warfarin.