National variation of ADHD diagnostic prevalence and medication use: health care providers and education policies.

OBJECTIVES: Attention-deficit hyperactivity disorder (ADHD) diagnostic prevalence and medication use vary across U.S. census regions, but little is known about state-level variation. The purpose of this study was to estimate this variation across states and examine whether a state's health care provider characteristics and education policies are associated with this variation.
METHODS: Logistic regression models were estimated with 69,505 children aged four to 17 from the state-stratified and nationally representative 2003 National Survey of Children's Health, conducted by the Centers for Disease Control and Prevention.
RESULTS: Diagnostic prevalence was higher in the South (odds ratio [OR]=1.42, p<.001) than in the West; among children with ADHD diagnoses, medication use was higher in the South (OR=1.60, p<.01) and the Midwest (OR=1.53, p<.01) versus the West. On these measures, several states differed from the U.S. averages, including some states that, on the basis of the regional patterns found above, would not be expected to differ: Michigan had a high diagnostic prevalence; Vermont, South Dakota, and Nebraska had low diagnostic prevalences; and Connecticut, New Jersey, and Kentucky had low medication rates. Both diagnosis and medication status were associated with the number, age, and type of physicians within a state, particularly pediatricians. However, state education policies were not significantly associated with either diagnostic prevalence or medication rates.
CONCLUSIONS: To better understand the association between a state's health care provider characteristics and both diagnostic prevalence and medication use, it may be fruitful to examine the content of provider continuing education programs, including the recommendations of major health professional organization guidelines to treat ADHD.