Participants who agreed to be enrolled into the protocol will have the initial research assessment session afterwards. This will be held at the outpatient clinic of the department of psychiatry, at University of Nebraska Medical Center. Participants will receive the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS), to confirm the diagnosis of ADHD/CD/ODD/DMDD, and to rule out any other psychiatric diagnoses listed in the exclusion criteria. Their IQ will be measured by the Wechsler Abbreviated Scale of Intelligence (2-subtest form). Irritability and emotional dysregulation will be measured by the Affective Reactivity Index (ARI). Only the children and adolescents with diagnoses of ADHD/CD/ODD/DMDD and clinically significant level of irritability/emotional dysregulation (score >4 on the ARI) will be enrolled in the study. CBCL, ICU, RPAQ will be used to measure the symptom profiles and functional impairment of patients with ADHD/CD/ODD/DMDD at the initiation and end point of their study participation.