Predicting Treatment Response to Stimulants in Adult ADHD Using Functional Magnetic Resonance Imaging

Inclusion Criteria: * Male or female adults ages 18-55 years * Right handed * A diagnosis current of childhood onset ADHD, according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) based on clinical assessment * A score of \> 20 on the Adult ADHD Investigator Symptom Report Scale (AISRS) or a CGI-Severity score of \> 4 (moderate severity) Exclusion Criteria: * A history of non-response or intolerance to stimulants at adequate doses as determined by the clinician * Pregnant or nursing females * Serious, unstable medical illnesses including hepatic, renal, gastroenterological, respiratory, cardiovascular, endocrinologic (thyroid), neurologic (seizure), immunologic, or hematologic disease * Glaucoma * Clinically unstable psychiatric conditions including suicidality, homocidality, bipolar disorder, psychosis, or lifetime history of a clinically serious condition potentially exacerbated by a stimulant, such as mania or psychosis * Tics or diagnosis of Tourette's syndrome * Current (within 3 months) DSM-IV criteria for abuse or dependence with any psychoactive substance other than nicotine * Current use of psychotropic medications * Current use of MAO Inhibitor or use within the past two weeks * Claustrophobia or an standard contraindications to MRI scanning (metal in body) * Investigator and his/her immediate family; defined as the investigator's spouse, parent, child, grandparent or grandchild