The purpose of this study is to evaluate the change in neuropsychological status from baseline to 6 months post-initiation of atomoxetine treatment in children ages 6 to 10.5 diagnosed with ADHD.

A) Patients:

Inclusion Criteria:

1. Patients must have ADHD, be outpatients, who are at least 6 years of age and not more than 10 years 6 months of age at Visit 1 so that all testing will be completed before the child reaches age 11.
2. Patients must have moderately severe symptoms of ADHD.
3. Patients must be able to swallow study drug capsules.

Exclusion Criteria:

1. Patients must not have Bipolar disorder, psychosis, autism, Asperger's syndrome, pervasive developmental disorder, or seizure disorder.
2. Patients must not be home-schooled.

B) Controls:

Subjects will be recruited by the investigator, age and gender-matched to the atomoxetine-treated patients.

Inclusion Criteria:

1) Control subjects must be assessed to be not diagnosed with a psychiatric disorder or a medically significant disorder

Exclusion Criteria:

1) Subjects must not be home-schooled.