 Participants will be screened with a medical history, physical examination, and blood and urine tests. Upon study entry, they will be interviewed about their moods, behaviors, and medical status during and immediately following their last pregnancy. Some women will be asked to participate in interviews, psychological tests, and blood tests. They will also complete self-rating scales and may be asked to collect samples of their urine. Women in Group 3 will complete self-rating scales for 6 months postpartum. Participants will participate in genetic studies that involve completing a questionnaire and providing a blood sample. If the participant allows, sisters and parents may be asked to provide a blood sample and undergo a psychiatric interview. 