County-level prevalence estimates of ADHD in children in the United States

Abstract

Purpose: Attention-deficit/hyperactivity disorder (ADHD) is a common childhood disorder often characterized by long-term impairments in family, academic, and social settings. Measuring the prevalence of ADHD is important as treatment options increase around the U.S. Prevalence data helps inform decisions by care providers, policymakers, and public health officials about allocating resources for ADHD. In addition, measuring geographic variation in prevalence estimates can facilitate hypothesis generation for future analytic work. Most U.S. studies of ADHD prevalence among children focus on national or demographic group rates.

Methods: Using a small area estimation approach and data from the 2016 to 2018 National Survey of Children's Health, we estimated childhood ADHD prevalence estimates at the census regional division, state, and county levels. The sample included approximately 70,000 children aged 5-17 years.

Results: The national ADHD rate was estimated to be 12.9% (95% Confidence Interval: 11.5%, 14.4%). Counties in the West South Central, East South Central, New England, and South Atlantic divisions had higher estimated rates of childhood ADHD (55.1%, 53.6%, 49.3%, and 46.2% of the counties had rates of 16% or greater, respectively) compared to counties in the Mountain, Mid Atlantic, West North Central, Pacific, and East North Central divisions (2.1%, 4%, 5.8%, 6.9%, and 11.7% of the counties had rates of 16% or greater, respectively).

Conclusions: These local-level rates are useful for decision-makers to target programs and direct sufficient ADHD resources based on communities' needs.

Keywords: Childhood attention-deficit/hyperactivity disorder; County-level; National Survey of Children's Health; Policy; Prevalence; Small area estimation.

Figure 1.. Estimated Proportion of Children Aged 5–17 Years with ADHD, County Level, 2016–2018

The lightest color represents counties with an ADHD estimate of 11% or lower. The second color in the gradient represents counties with an ADHD estimate between 12% and 15%. The third color in the gradient represents counties with an ADHD estimate between 16% and 19%. The darkest color represents counties with an ADHD estimate of 20% or higher. The lighter the color of the county, the lower the ADHD prevalence estimate. The darker the color of the county, the higher the ADHD prevalence estimate. For example, counties in the southern part of the U.S. have higher ADHD prevalence than counties in western states.

Figure 2.. Hot and Cold Spots of ADHD Prevalence Estimates in U.S. Children Aged 5–17 Years, 2016–2018

The hot spot analysis uses the Getis-Ord Gi* statistic which is optimized by correcting for multiple testing and spatial dependence using the False Discovery Rates. Statistically significant clusters of high ADHD prevalence rates (hot spots) are shown in orange and red, while significant clusters of low ADHD prevalence rates (cold spots) are shown in shades of blue, with darker reds and blues indicating greater certainty. The South Atlantic, East South Central, parts of West South Central, and New England regional divisions are hot spots of ADHD. Nearly all the remaining regional divisions appear as cold spots of ADHD.