Comparison of Atomoxetine Plus Either Comparator or Placebo in Children With ADHD Who Haven't Responded to Stimulant Therapy

Inclusion Criteria: * Patients will be at least 6 years of age and not more than 12 years of age at visit 1 * Patients must meet DSM-IV diagnostic criteria for ADHD * Patients must be retrospectively identified as stimulant non-responders * Patients must be of normal intelligence as assessed by the investigator (that is, without a general impairment of intelligence and likely, in the investigator's judgment, to achieve a score of greater than or equal to 70 on an IQ test) * Patients must be able to swallow capsules Exclusion Criteria: * Patients who weigh less than 22 kg or more than 60 kg at study entry * Patients who have a history of Bipolar I or Bipolar II Disorder, psychosis, or pervasive developmental disorder * Patients who meet DSM-IV criteria for anxiety disorder or autism * Patients with a history of any seizure disorder and/or Rolandic seizures (other than febrile seizures) or prior electroencephalogram (ECG) abnormalities in the absence of seizures, or patients who have taken (or are currently taking) anticonvulsants for seizure control * Patients with a history of severe allergies to more than one class of medication or multiple adverse drug reactions, including hypersensitivity to MPH