The main purpose of this study is to investigate how the brain responds to a procedure known as transcranial direct current stimulation (tDCS) and how tDCS affects performance on a behavioral task. Research suggest that this procedure leads to improvement in brain and behavioral measures of inhibitory control (controlling impulses) in healthy control participants. The investigators want to explore whether the same improvement will be seen in kids with ADHD.

Inclusion Criteria:

• Clinical diagnosis of ADHD
• Parent informed consent and child assent

Exclusion Criteria:

• Intracranial pathology from a known genetic disorder (e.g., Neurofibromatosis Type 1 (NF1), tuberous sclerosis) or from acquired neurologic disease (e.g. stroke, tumor), cerebral palsy, history of severe head injury, or significant dysmorphology
• History of fainting spells of unknown or undetermined etiology that might constitute seizures
• History of seizures, diagnosis of epilepsy, or immediate (1st degree relative) family history epilepsy
• Chronic (particularly) uncontrolled medical conditions that may cause a medical emergency in case of a provoked seizure (cardiac malformation, cardiac dysrhythmia, asthma, etc.)
• History of head injury resulting in prolonged loss of consciousness
• Substance abuse or dependence within the past six months
• Chronic treatment with prescription medications that decrease cortical seizure threshold that the patient is unable to withhold from taking during study visits
• Damaged skin on the scalp (i.e., skin with ingrown hairs, acne, razor nicks, wounds that have not healed, recent scar tissue, broken skin, etc.)

Patients with ADHD