Quillivant Oral Suspension (Quillivant XR) in the Treatment of Attention Deficit Hyperactivity Disorder (ADHD)

Inclusion Criteria: * Male or female from 6 to 12 years of age at the time of screening, inclusive. * Diagnosis of ADHD by a Psychiatrist, Psychologist, Developmental Pediatrician, or a Pediatrician meeting diagnostic criteria for ADHD (DSM-IV). A Schedule for Affective Disorders and Schizophrenia for School Age Children (K-SADS)16 was administered on all subjects to assist in diagnostic process. * A clinician-administered Clinical Global Impression of Severity (CGI-S) score of 3 or greater. An Attention Deficit Hyperactivity Disorder Rating Scale (ADHD-RS) score at screening or baseline greater than or equal to the 90th percentile normative values for gender and age in at least one of the following categories: the hyperactive-impulsive subscale, inattentive subscale or the total score. * Subject must have been in need of pharmacological treatment for ADHD. * Subjects taking a medication to control ADHD at the time of screening must have been experiencing suboptimal efficacy, a safety or tolerability issue or in need of a long-acting liquid formulation. * For subjects taking any daily medication at screening aside from ADHD medication: parent or legal guardian agreed that there would be no elective changes in subject's medications during the study (10 weeks total). Exclusion Criteria: * Excluded comorbid psychiatric diagnoses: DSM-IV Axis I diagnosis (active) other than ADHD, with the exception of Specific Phobias, Learning Disorders, Motor Skills Disorders, Communication Disorders, Oppositional Defiant Disorder, Elimination Disorders, Sleep Disorders, and Adjustment Disorders. * Clinically significant cognitive impairment as assessed in the clinical judgment of the Investigator. In cases where this was not clear, study staff were permitted to administer a Wechsler Abbreviated Scale of Intelligence (WASI)17 to estimate the intelligence quotient (IQ). Significant cognitive impairment for this protocol was defined as an estimated IQ below 80. * Subjects with chronic medical illnesses including seizure disorder (excluding a history of febrile seizures), severe hypertension, thyroid disease, structural cardiac disorders, serious cardiac conditions, serious arrhythmias, cardiomyopathy, glaucoma, Tourette's Disorder, family history of Tourette's Disorder or tics. * Use of monoamine oxidase inhibitors within 30 days of the screening visit. * Use of any psychotropic medication (except sedative hypnotics prescribed as a sleep aid at a stable dose for at least 30 days prior to screening, at bedtime only). Use of stimulant medication for control of ADHD at screening was permitted if inclusion criterion number 6 was met.