Healthy controls will be recruited through email announcements at MGH, internet website at Harvard, and flyers posted at the Massachusetts General Hospital and in the community (e.g., community centers, public libraries, coffee shops, restaurants, and laundromats). Subjects with major depression will be recruited through the Depression Clinic and Research Program at MGH and flyers posted at MGH. Subjects with bipolar disorder will be recruited through the Bipolar Clinic and Research Program at MGH and flyers posted at MGH.