Clinical Trial of Pramipexole in Bipolar Depression

The purpose of this study is to examine the safety and effectiveness of the drug pramipexole given in combination with lithium or divalproex for the short-term treatment of acute depression in patients with bipolar disorder. Bipolar disorder is a severe, chronic, and often life-threatening illness. Treatments for acute unipolar depression have been extensively researched. However, despite the availability of a wide range of antidepressant drugs, a significant proportion of depressed patients fail to respond to first-line antidepressant treatment. Novel and improved therapeutics for bipolar depression are needed. This study will evaluate the antidepressant properties of pramipexole. This study will be conducted in three phases. Phase 1 is a 14-day washout period in which participants will be tapered off all their psychiatric medicines except divalproex or lithium. Participants will also be asked to adhere to a low caffeine and low monoamine diet. During Phase 2, participants will be randomly assigned to receive either pramipexole or placebo (an inactive pill) for 6 weeks. Participants who respond to treatment will be given either open-label pramipexole or another clinical treatment. Participants will be screened with a medical history, physical examination, electrocardiogram (EKG), blood and urine tests, and a psychiatric evaluation. Women of childbearing potential will have a pregnancy test. Participants will have a physical exam and EKG at study entry and study completion. Blood will be drawn at various times throughout the study. Pulse and blood pressure measurements will be taken daily. Weekly interviews will be conducted. Participants and a control group of healthy volunteers will undergo positron emission tomography (PET) and magnetic resonance imaging (MRI) scans of the brain.