Rising Trends of Childhood Attention-Deficit/Hyperactivity Disorder in a Large Integrated Healthcare Delivery System in Southern California, 2010-2021

Objective: To evaluate trends of attention-deficit/hyperactivity disorder (ADHD) diagnosis rates among children aged 5-17 years over the past decade (2010-2021) and to investigate whether there have been differences in temporal changes based on race and ethnicity, sex, or income. Study design: Childhood ADHD diagnosis was ascertained from electronic health records using International Classification of Diseases ninth revision (314.xx) and International Classification of Diseases tenth revision (F90.x) codes. Data were stratified by child's sex, race and ethnicity, and household income, and rates of ADHD were estimated before and after adjustment for potential confounders. Results: The overall ADHD diagnosis rates increased from 3.5% in 2010 to 4.0% in 2021. ADHD diagnosis was most prevalent among White children (6.1%), then Black (4.6%), Other/multiple (3.7%), Hispanic (3.1%), and Asian/Pacific Islander (PI) (1.7%). ADHD was also highly prevalent among boys (73.3%) or family income≥$70,000 (50.0%). ADHD diagnosis increased among Black (4.2% to 5.1%), Hispanic (2.8% to 3.6%), and Asian/PI children (1.5% to 2.0%) but remained stable for White (6.2% to 6.1%) and Other/multiple race/ethnic children (3.7% to 3.7%). Increases in the prevalence among girls were also observed. Conclusion: The prevalence of ADHD in children has risen with the largest increases observed for Black, Hispanic, and Asian/PI children. Rates among less affluent families and girls have also been increasing, narrowing the gaps in diagnosis rates previously observed. These increases may reflect improvements in screening and provision of care among demographics where ADHD has been historically underdiagnosed.