Epidemiologic issues in ADHD

The science of public health is epidemiology and this type of research uses population-based methods to identify etiologic pathways to disease or disorder development. It also provides the foundation for research in prevention, risk-factor analysis, and other relevant areas. Little rigorous scientific study of comorbidity, etiology, risk factors, or prevention of Attention-Deficit Hyperactivity Disorder (ADHD) has been completed and the studies available have relied heavily on clinic-based populations rather than on population-based sampling. However, such rough estimates of comorbidity, secondary conditions, and health risk behaviors among those with ADHD are quite high and range from 30% to 60% for highly comorbid conditions. ADHD is a very prevalent childhood disorder with a number of commonly comorbid conditions that present or develop in time with significant additional social, learning, and psychological impairment.

Prevalence estimates of ADHD have historically varied over time ranging from as low as under 1% to as high as nearly 20% of school-age children. There is no systematic monitoring of ADHD, no gold standard for epidemiologic research of the disorder, and minimal population-based epidemiologic research of ADHD in the United States. Consequently, even rough estimates of the prevalence provide no meaningful indication of the level of burden this disorder poses in our society. Unfortunately, current research endeavors provide insufficient information to explore, even roughly, basic descriptive epidemiologic questions such as how the disorder may vary by race, ethnicity, socio-economic status, and age. Currently there is no known etiology for the disorder; therefore, epidemiologic research is imperative. However there is a paucity of such rigorous science in the ADHD field.

An internal CDC workgroup hosted a one-day meeting with several ADHD experts on this topic to answer specific questions and generate ideas for needed research. The executive summary of this meeting provides detailed questions and answers to related issues.

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