Safety, Tolerability and Efficacy Study of ABT-089 in Adults With Attention-Deficit/Hyperactivity Disorder (ADHD)

Inclusion Criteria: * Have voluntarily signed an informed consent form. * Meet diagnostic criteria for attention-deficit/hyperactivity disorder (ADHD) based on detailed evaluation and interview with subject. * Subject is generally in good health based on medical history, physical examination, clinical lab tests and ECG. * Female subjects of child-bearing potential must have a negative urine pregnancy test at screening and baseline and agree to comply with applicable contraceptive requirements. * Male subjects must agree to comply with applicable contraceptive requirements. * Subject is able to keep required appointments for clinic visits and all tests, including blood draws and examinations. Exclusion Criteria: * Subject has a current or past diagnosis of schizoaffective disorder, schizophrenia, obsessive-compulsive disorder, drug-induced psychosis, bipolar disorder, psychotic disorder. * Current diagnosis of major depressive disorder, generalized anxiety disorder, PTSD or has a sleep disorder requiring treatment of any kind. * Subject has a history of, or ongoing, serious medical problem. * Subject has a history of significant allergic reaction to any drug. * Subject is planning to begin any type of behavioral or psychotherapy for treatment of ADHD. * Subject requires ongoing treatment with any psychiatric medication.