Efficacy of Atomoxetine for ADHD in Adolescents and Young Adults With SUD

Inclusion Criteria: * Male and female outpatients 15-30 years. * Subjects with a DSM-IV diagnosis of ADHD (combined or inattentive subtype) as determined by clinical evaluation and/or ADHD module of structured diagnostic interview, completed by the study clinician. * Subjects with a current or recent (within three months) substance use disorder (drugs or alcohol) as determined through clinical evaluation and/or ascertained through structured diagnostic interview. * Subjects with an ADHD CGI-S of \>= 4 (moderate impairment). Exclusion Criteria: * Pregnant or nursing females. * Subjects with a clinically unstable medical condition that will either jeopardize patient safety or affect the scientific merit of the study, or who undergo a change in treatment during the study. * Recent history of intravenous drug use, or subjects who have current DSM-IV criteria for abuse or dependence of cocaine, MDA, MDMA, gammahydroxybutyrate, methamphetamines, amphetamines, opioids, PCP, or benzodiazepines that in the opinion of the investigator will interfere in their ability to participate safely in the study. * Subjects with Mental Retardation or Organic Brain Syndromes. * Subjects who are psychotic or have a history of bipolar disorder. * Participants who are taking any psychotropic or anti-SUD medications will be excluded from the study. * Current DSM-IV diagnosis of major depression, depressive disorders, or anorexia as manifested by clinical interviews.