Single Versus Combination Medication Treatment for Children With Attention Deficit Hyperactivity Disorder

Inclusion Criteria: * Diagnosis of DSM-IV ADHD by K-SADS-PL and confirmed by clinical interview * Clinical Global Impression-Severity score of at least 4 for ADHD * Resided with primary caretaker for at least 6 months prior to study entry Exclusion Criteria: * History of autism, pervasive developmental disorder, chronic tic disorder, psychosis, or bipolar disorder * Current major depression or panic disorder * Systolic or diastolic blood pressure at screening greater than the 95th percentile or less than the 5th percentile for age and body mass index (BMI) * Any medical condition that might make stimulant or alpha agonist therapy medically inadvisable * Need for chronic use of other medications with central nervous system effects * Pregnant, breastfeeding, or beyond menarche and has a positive urine pregnancy test * History of structural heart defects, syncope, or fainting while exercising * Clinically significant cardiac abnormality as determined by echocardiogram (ECG) at study entry * Mental retardation as determined by clinical functional assessment and an IQ estimate of less than 70 based on Wechsler Adult Intelligence Scale (WAIS) subtests