Phase 2: Enrolment & Behavior Management Training At Visit 2 families will begin a standardized course of behavior management training. The purpose of this phase will be to ensure that non-pharmacological intervention is attempted prior to initiation of study medication. Four visits, each of 90 minutes duration (Study Visits 2-5), will be conducted over a period of 2-4 weeks. Families will be expected to complete all 4 sessions of behavioural training within a 4 week period. Primary caregivers will be the primary attendees for these sessions and content will include education regarding ADHD, and behavior management techniques, including the proper use of contingency management, time-out, and response cost. Session content will be adapted from several well-established and empirically validated interventions.