Treatment of Impulsive Aggression in Subjects With ADHD in Conjunction With Standard ADHD Treatment (CHIME 2)

Inclusion Criteria: * Otherwise healthy male or female subjects, age 6 to 12 years at the time of screening with a primary diagnosis of ADHD and currently receiving monotherapy treatment with an optimized FDA-approved ADHD medication. * Impulsive aggression will be confirmed at screening using R-MOAS and Vitiello Aggression Scale. Exclusion Criteria: * Current or lifetime diagnosis of epilepsy, major depressive disorder, bipolar disorder, schizophrenia or a related disorder, personality disorder, Tourette's disorder, or psychosis not otherwise specified. * Currently meeting DSM criteria for autism spectrum disorder, pervasive developmental disorder, obsessive-compulsive disorder, post-traumatic stress disorder, or any other anxiety disorder as the primary diagnosis. * Known or suspected intelligence quotient (IQ) \< 70, suicidality, pregnancy, or substance or alcohol abuse.