Role of Theta Frequency Oscillations in Proactive and Reactive Control Processes in Youth With Attention Deficit Hyperactivity Disorder (ADHD) and Obsessive Compulsive Disorder (OCD)

Background: Attention deficit hyperactivity disorder (ADHD) is common in children. It can cause problems with attention and the ability to control actions and impulses. Obsessive compulsive disorder (OCD) is less common in children but not rare. It involves ongoing thoughts, urges, impulses, and repeated behaviors. Researchers want to study differences in brain activity between healthy children, those with ADHD, and those with OCD. Objective: To learn more about how the brain controls thinking and behavior. Eligibility: People aged 10 to 17 years with ADHD, OCD, or neither. Design: Participants will have 3 to 10 clinic visits in up to 1 year. Each visit will last 2 to 3 hours. Three visits are required: Behavioral. Participants will complete a computer task. Their mood, memory, attention, and thinking skills will be tested. EEG. Participants will undergo electroencephalography (EEG) to measure signals in their brain. Small electrodes will be placed on the scalp. A cap will be stretched over the head. Signals will be recorded while participants rest or do tasks on a computer. MRI. Participants will have a magnetic resonance imaging scan (MRI). They will lie on a table that rolls into a tube. The MRI will take pictures of their brain while they do tasks on a computer. Seven more visits are optional. These include 2 more EEG visits and 2 more MRI visits. Three will be magnetoencephalography (MEG) visits: MEG measures small magnetic field changes in the brain. A helmet with sensors will be placed on the head. Brain changes will be recorded while participants rest or do tasks on a computer.