A single arm, open-label, phase 3 multicenter study to evaluate the effectiveness and tolerability of atomoxetine (given once daily, target dose 1.2 mg/kg/day), as perceived by patients, parents and physicians, and its impact on self-esteem in adolescents (aged 12 through 17 years) with Attention-Deficit/Hyperactivity Disorder treated as outpatients in Germany. An 8-week treatment phase is followed by a 16-week extension period.

Inclusion Criteria:

• Male or female outpatients who are at least 12 years of age and who will not have reached their 18th birthday
• Diagnosis of ADHD
• Normal intelligence

Exclusion Criteria:

• Weigh less than 30 kg or more than 85 kg at study entry
• Other relevant psychiatric diagnoses
• Are at serious suicidal risk as determined by the investigator
• Have a history of severe allergies
• Alcohol or drug abuse within the past 3 months
• Are female patients who are pregnant or breast-feeding. Sexually active females must use a medically acceptable method of contraception.