A widely used pesticide may be responsible for the development of ADHD (attention deficit hyperactivity disorder) by impacting on the brain’s dopamine system. ADHD affects children with an estimated 6.4 million diagnosed as of 2011. It affects boys more than girls and is characterized by an inability to sit still, pay attention and follow directions.
The research study published in the Journal of the Federation of American Societies for Experimental Biology (FASEB) determined that mice exposed to pyrethroid pesticide deltamethrin in utero and through lactation exhibited several features of ADHD, including dysfunctional dopamine signaling in the brain, hyperactivity, working memory, attention deficits and impulsive-like behavior.
The researchers used data from the Centers for Disease Control, National Health and Nutrition Examination Survey (NHANES) and the study analyzed health care questionnaires and urine samples of 2,123 children and adolescents. Researchers asked parents whether a physician had ever diagnosed their child with ADHD and cross-referenced each child’s prescription drug history to determine if any of the most common ADHD medications had been prescribed. Children with higher pyrethroid pesticide metabolite levels in their urine were more than twice as likely to be diagnosed with ADHD.
“Although we can’t change genetic susceptibility to ADHD, there may be modifiable environmental factors, including exposures to pesticides that we should be examining in more detail,” said lead author Jason Richardson, associate professor in the Department and Environmental and Occupational Medicine at Rutgers Robert Wood Johnson Medical School. “We need to make sure these pesticides are being used correctly and not unduly expose those who may be at a higher risk,” Richardson said.
The researchers suggest that young children and pregnant women may be more susceptible to pesticide exposure because their bodies do not metabolize the chemicals as quickly. This is why, Richardson says, human studies need to be conducted to determine how exposure affects the developing fetus and young children.
J. R. Richardson, M. M. Taylor, S. L. Shalat, T. S. Guillot, W. M. Caudle, M. M. Hossain, T. A. Mathews, S. R. Jones, D. A. Cory-Slechta, G. W. Miller. Developmental pesticide exposure reproduces features of attention deficit hyperactivity disorder. The FASEB Journal, 2015; DOI: 10.1096/fj.14-260901