Effects of Atypical Antipsychotics on Brain Function in Children and Teens With Conduct Disorders

Background: \- Some children and teenagers have conditions known as conduct disorders. They often have long-term chronic behavior problems, such as defiant behavior or violence. Conduct disorders are often treated with antipsychotic medication. Researchers want to study two types of newer antipsychotics (aripiprizole and risperidone) for children and adolescents with conduct disorders. They will look at how these drugs affect brain activity. To do so, they will give brain activity tests using magnetic resonance imaging (MRI). The tests will compare the results from healthy volunteer children and teens to those of others with behavior problems. Objectives: \- To see how atypical antipsychotics affect brain activity of children and teenagers with conduct disorders. Eligibility: * Children and teenagers between 10 and 18 years of age who have a conduct disorder and are taking aripiprizole. * Children and teenagers between 10 and 18 years of age who have a conduct disorder and are taking risperidone. * Children and teenagers between 10 and 18 years of age who have a conduct disorder and are not taking an atypical antipsychotic. * Healthy volunteers between 10 and 18 years of age. Design: * Participants will be screened with a physical exam and medical history. Parents/guardians will be asked questions about their child s feelings, experiences, and behavior. Participants will also answer questions about their feelings and moods. * This study will involve two visits. Each visit will involve MRI scanning. * At the first visit, participants will have memory and thinking tests. The tests will involve making decisions or playing games. Some of these tests will use MRI scanning to look at brain activity. * The second visit will be 3 to 5 months after the first visit. The tests from the first visit will be repeated.