A Glutamate Transporter GLT1, in the Treatment of Bipolar Disorder

This study examines if Ceftriaxone, an antibiotic, will improve symptoms of depression in Bipolar Disorder. Purpose: This study will examine whether the drug ceftriaxone can help patients with bipolar depression during short-term treatment of symptoms such as depressed mood, psychomotor retardation (slowed down thinking and movements), and problems with sleep. Recent studies suggest that abnormalities in the brain levels of the chemical glutamate may be involved in causing depression. Ceftriaxone increases a protein in the brain called GLT1, which is responsible for regulating brain levels of glutamate. People between 18 and 65 years of age with bipolar disorder who are currently in a depressive episode of at least 4 weeks but no longer than 12 months duration may be eligible for this study. Participants are admitted to the NIH Clinical Center for about 10 weeks. During the first 1 to 2 weeks, they are evaluated and tapered off any antidepressant or mood stabilizers they have been taking. They remain free of all medication for 2 weeks and are then randomly assigned to take either ceftriaxone or placebo for 6 weeks. The study drugs are given intravenously (through a vein) every day. To minimize discomfort, patients are given a PICC line - a tube that is inserted in a vein in the arm and remains there for the duration of drug treatment. This prevents the need for repeated intravenous injections. Patients have a physical examination at the beginning and at the end of the study and two electrocardiograms (ECG) during the study. They are evaluated periodically with a series of psychiatric rating scales to determine the effects of the study drug on mood and thinking and they have periodic blood tests to assess their health status. In addition, patients are asked to undergo a lumbar puncture (spinal tap) twice during the study to collect a sample of cerebrospinal fluid (CSF, the fluid that bathes the brain and spinal cord). The CSF is examined to try to understand how