Researches recently reported that children with high levels of the pesticide malathion in their urine are at greater risk of contracting Attention Deficit Hyperactivity Disorder, or ADHD. Epidemiologist Marc G. Weisskopf of Harvard University's School of Public Health and his colleagues studied data on 1,139 children from the National Health and Nutrition Examination Survey over a four-year period. Weisskopf suggests that similar studies "'should raise eyebrows and get people concerned enough to want to follow up intensively.'"