This study is a randomized, phase III, multicenter, placebo-controlled, parallel-group, forced-dose titration in which adolescent subjects (12 to 17 years of age inclusive) with ADHD will be randomized to PRC-063 (25, 45, 70 or 85 mg) or placebo for four weeks of double-blind evaluation of safety and efficacy. The study will have four phases: (1) screening and 1-week washout; (2)baseline and double-blind, forced-dose titration over a 2-week period; (3) double-blind evaluation over a 2-week period; and (4) a 14-day safety follow-up. Subjects will be required to visit the site 6 times over a 5 week period.