The purpose of this project is to evaluate environmental, reproductive, and familial risk factors for ADHD within a population-based cohort. We are in the process of screening all 8,000 elementary school students in the Johnston County School system for ADHD, first through teacher completed forms and later through parent interviews. The primary aims of the project are to describe the prevalence of ADHD and how it varies by age, race, gender, and SES, to test the hypothesis that preterm and post-term births are at higher risk for ADHD and to evaluate the role of maternal smoking, maternal occupation, maternal alcohol consumption and pregnancy complications as risk factors for ADHD.We have developed a practical method to apply clinical case criteria for ADHD to an epidemiologic setting. This allows us to provide important information that has not previously been available on prevalence, risk factors, and treatment patterns of ADHD.In the first year of data collection, we obtained an 83% response rate in screening the first 8 schools. Our initial data suggest the prevalence of diagnosed ADHD is about 10% and that about 7% of all children in the elementary schools are taking medication to treat ADHD. After screening the population, data from a pretest conducted in 4 schools suggests that the true prevalence might be about 15%, three times the official estimate from DSM-IV. In addition, we found that almost 40% of the cases had not been previously diagnosed and almost a third of the children being treated with medication were still showing enough symptoms and impairment to look like cases. - Attention Deficit Disorder, preterm birth, ADHD, lead, children, pesticides, epidemiology, behavior, - Human Subjects: Interview, Questionaires, or Surveys Only