Participants will be allowed to skip the Parent Training Phase if either of the following criteria are met: 1) the patient and her/his primary caregiver have participated in the last 12 months in a documented course of non-pharmacological treatment and resulted in minimal benefit; and/or 2) the patient exhibits ADHD symptoms and impairment that are severe enough to warrant moving immediately to the medication phase of the study. Each of these criteria will be assessed by the site investigator in consultation with the study medical monitor and a coordinating investigator. See Section 6.1.1 for a detailed list of procedures. The initiation of any additional psychotherapy during the study will not be permitted. However, patients that are already participating in psychotherapy that was initiated prior to the study will be permitted to continue in these programs.