Eligible subjects are adolescents, 12 to \<18 years of age, with a primary diagnosis of ADHD based on criteria established by the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) criteria. Subjects will be randomized in a 1:1:1 ratio to receive solriamfetol dose A, solriamfetol dose B or placebo once daily for 6 weeks.