Comparison of Lisdexamfetamine Dimesylate With Atomoxetine HCl in Attention-Deficit/Hyperactivity Disorder (ADHD) Subjects With an Inadequate Response to Methylphenidate

Inclusion Criteria: * Subject has had an historical or current inadequate response to methylphenidate (MPH) treatment. Inadequate response includes but is not limited to the presence of some residual symptoms, with associated impairment inadequate duration of action and/or variability of symptom control, and/or Investigator feels that the subject may derive benefit from an alternative drug treatment to MPH therapy. * Subject is a male or female aged 6-17 years inclusive at the time of consent * Subject must meet Diagnostic and Statistical Manual of Mental Disorders, fourth edition. - Text Revision (DSM IV TR) criteria for a primary diagnosis of ADHD based on a detailed psychiatric evaluation * Subject must have a baseline ADHD-RS-IV total score 28. Exclusion Criteria: * Subject has taken more than 1 MPH treatment (for example, 2 or more different MPH treatments). Examples include but are not limited to RITALIN immediate release (IR) and EQUASYM IR; MEDIKINET IR and CONCERTA; RITALIN long-acting LA and CONCERTA. Note: this does not include subjects who have taken IR MPH for dose titration on a short-term basis (for example, £4 weeks) with an adequate response * In the Investigator's judgement, subject has failed to respond to more than 1 previous course(s) of MPH treatment. Failure to respond includes worsening of symptoms or no change/minimal improvement of symptoms. * Subject has previously been exposed to STRATTERA or to amphetamine therapy * Subject has previously demonstrated intolerable side effects to 1 MPH treatment which limited titration to acceptable efficacy or that required a decrease in dose resulting in unacceptable tolerability and/or efficacy * Subject has a current, controlled (requiring a restricted medication) or uncontrolled, comorbid psychiatric diagnosis with significant symptoms such as any severe comorbid Axis II disorder or severe Axis I disorder or other symptomatic manifestations, such as agitated states, marked anxiety, or tension that, in the opinion of the examining physician, will contraindicate treatment with SPD489 or STRATTERA or confound efficacy or safety assessments. * Subject has a conduct disorder. Oppositional Defiant Disorder is not exclusionary.