We are trying to understand what causes bipolar disorder and how medications treat bipolar depression. Particularly, we are looking at the importance of inflammation in the process. If you participate, you will have two different brain scans (MRI and PET scan). You will also have an experimental treatment for your depression named N-acetyl cysteine (NAC). The study is funded by the Columbia University Irving Institute to improve the treatment of bipolar disorder. Please contact us if you are interested in participating. Up to $600 in compensation if you are eligible and choose to participate. Up to 6 months of treatment for depression at no cost to you.

Inclusion Criteria:

• Bipolar 2 disorder and meets criteria for a major depressive episode
• Age 18-60
• Females of child-bearing potential must be willing to use an acceptable method of birth control throughout the study
• Not currently taking psychotropic medications besides those allowed in the clinical trial

Exclusion Criteria:

• Failed trial or intolerable side effects of NAC
• Diagnosis of other major psychiatric disorders such as lifetime schizophrenia, schizoaffective disorder, psychotic features of bipolar disorder, current drug or alcohol abuse or recent drug or alcohol dependence
• Significant active physical illness, including blood dyscrasias, lymphomas, hypersplenism, endocrinopathies, renal failure, chronic obstructive lung disease, autonomic neuropathies, peripheral vascular disease. Any disorders with inflammation, malignancy, autoimmune or infectious etiology. Systolic blood pressure >140 or diastolic blood pressure > 100 Hemoglobin <11 in females or <13 in males
• Metal implants, pacemaker, metal prostheses, metal orthodontic appliances or shrapnel in the body
• Current, past or anticipated exposure to radiation