RecruitingDrug trialStudies of Brain Function and Course of Illness in Pediatric Bipolar DisorderThis study seeks to learn more about the symptoms of severe mood dysregulation in children and adolescents ages 7-17. Children and adolescents with severe mood dysregulation (SMD) display chronic anger, sadness, or irritability, as well as hyperarousal (such as insomnia, distractibility, hyperactivity) and extreme responses to frustration (such as frequent, severe temper tantrums). Researchers will describe the moods and behaviors of children with these symptoms and use specialized testing and brain imaging to learn about the brain changes associated with this disorder.