A Dose-Ranging, Cross-over Study of the Safety and Efficacy of ABT-089 in Adults With Attention-Deficit/Hyperactivity Disorder (ADHD)

Inclusion Criteria: * Meet criteria for attention deficit hyperactivity disorder * Have voluntarily signed an informed consent form * Are between 18 and 60 years of age * Will use contraceptive methods during the study * Women must not be pregnant or breast-feeding * Must be in generally good health * Are fluent in English Exclusion Criteria: * They have a current or past diagnosis of schizoaffective disorder, schizophrenia, obsessive-compulsive disorder, drug-induced psychosis, bipolar disorder, psychotic disorder or mental retardation * They have a current diagnosis of major depressive episode, generalized anxiety disorder (GAD), or post-traumatic stress disorder (PTSD) or have a clinically significant sleep disorder requiring treatment * They require ongoing treatment or expected treatment with any psychotropic medication, including anxiolytics, antipsychotics, anticonvulsants, antidepressants or mood stabilizers * They failed to respond to two or more adequate trials of FDA-approved ADHD medication * They have violent, homicidal or suicidal ideation * They have a significant history of medical diagnoses, seizure disorder, Tourette's syndrome or a central nervous system (CNS) disease, excluding ADHD * They have a urine drug screen that is positive for alcohol or drugs of abuse * They have a history of substance or alcohol disorder (abuse/dependence) during the last 3 months