ADHD and Psychiatric Comorbidity: Functional Outcomes in a School-Based Sample of Children.

Investigate the prevalence and impact of psychiatric comorbidities in community-based samples of schoolchildren with/without ADHD. Teachers and parents screened children in South Carolina (SC; = 4,604) and Oklahoma (OK; = 12,626) for ADHD. Parents of high-screen and selected low-screen children received diagnostic interviews (SC: = 479; OK: = 577). Psychiatric disorders were increased among children with ADHD and were associated with low academic performance. Conduct disorder/oppositional defiant disorder (CD/ODD) were associated with grade retention (ODD/CD + ADHD: odds ratio [OR] = 3.0; confidence interval [CI] = [1.5, 5.9]; ODD/CD without ADHD: OR = 4.0; CI = [1.7, 9.7]). School discipline/police involvement was associated with ADHD alone (OR = 3.2; CI = [1.5, 6.8]), ADHD + CD/ODD (OR = 14.1, CI = [7.3, 27.1]), ADHD + anxiety/depression (OR = 4.8, CI = [1.6, 14.8]), and CD/ODD alone (OR = 2.8, CI = [1.2, 6.4]). Children with ADHD + anxiety/depression had tenfold risk for poor academic performance (OR = 10.8; CI = [2.4, 49.1]) compared to children with ADHD alone. This should be interpreted with caution due to the wide confidence interval. Most children with ADHD have psychiatric comorbidities, which worsens functional outcomes. The pattern of outcomes varies by type of comorbidity.