This 9-week study will include participants who are healthy, have BD, or are siblings of subject with BD. All potential participants will undergo initial testing, which will include a physical examination, blood tests, and an electrocardiogram (EKG). Participants will also be asked to answer questions about their mental health, drug use, personality, family history, and psychological well-being. Eligible participants will then return on a different day to undergo an MRI scan, taking 4 hours to complete. During the scan, participants will be asked to perform tasks designed to show changes in blood flow in specific brain regions. These tasks will include listening to sounds and looking at various letters, words, and pictures. This will mark the completion of the study for healthy participants, first degree relatives, and those participants with BD who do not wish to receive medication treatment.