Abstract Objective To evaluate the presence and severity of attention-deficit/hyperactivity disorder (ADHD) in children in the United States, and to explore the relationship between ADHD, functional cognitive impairments, access to evidence-based treatments, and adequate health insurance. Method This study included children aged six to 17 (n = 34,109) from the 2022 National Survey of Children’s Health (NSCH) representing diverse races, ethnicities, and socioeconomic statuses. Data was collected on ADHD diagnosis, severity, insurance coverage, medication/behavioral treatment, and cognitive impacts. Results Of the participants, 10.5% reported ADHD, with 4.4% reporting mild symptoms and 6% reporting moderate to severe symptoms. The more severe ADHD symptoms were, the greater impact on cognitive performance was noted χ2(2,N = 4772) = 705 p < 0.001; with mild ADHD rarely impacting cognition resid.(1,2) = −421. Only 13.9% of children with ADHD is currently covered by health insurance, and only 6.6% of children with ADHD have health insurance to cover their mental and/or behavioral health services. Of those insured, children with severe ADHD were more likely to have insufficient coverage χ2(8,N = 4642) = 362 p < 0.001; resid.(3.3) = −23.5. Conclusions The study revealed a considerable 10.5% of U.S. children currently have ADHD, with greater cognitive impacts revealed for children with greater severity of symptoms. Results also revealed critical disparities in ADHD management, and in turn their cognitive functioning. While 59.7% reported insurance always covered mental health needs, and 13.9% indicated inconsistent coverage, contributing to treatment gaps. This lack of coverage particularly affects children with moderate to severe ADHD, exacerbating cognitive impacts. These findings underscore the need for comprehensive ADHD care and improved, consistent mental health coverage.