Atomoxetine for Treating Attention Deficit Hyperactivity Disorder in Young Children

Inclusion Criteria: * Parent and child must be English speaking * Child has been living with parent/guardian for at least six months * Meets criteria for ADHD on the DISC, on clinical interview, and on clinical consensus conference * ADHD is primary disorder with symptoms present for at least 9 months * ADHD-IV-Rating Scale (ADHD-IV-RS)score that is at least 1.5 standard deviations above age and sex norms * Score of 55 or below on the Children's Global Assessment Scale * Score of 4 or greater on the Clinical Global Impression Scale * Estimated Intelligence Quotient (IQ) of 70 or greater * Currently participating in school at least 2 half-days per week * Able to identify a teacher who can make valid assessments * Patient and parent are able to attend regular study visits Exclusion Criteria: * Currently taking other psychotropic medications or other medications with effects on the central nervous system * Currently being treated effectively with atomoxetine * Major medical conditions that might interfere with study medications * History of or current clinically significant kidney illness * Evidence of adjustment disorder, autism, psychosis, bipolar disorder, suicide ideations, or any other psychiatric disorder requiring treatment with additional psychotropic medication * History of physical, sexual, or emotional abuse impacting clinical presentation * Prior failure to respond to an adequate trial of atomoxetine