Common pesticide may increase risk of ADHD

Exposure to a common household pesticide may increase the risk of attention deficit hyperactivity disorder (ADHD) in children, a new study has found.
Researchers from Rutgers University and colleagues from Emory University, the University of Rochester Medical Center, and Wake Forest University found that mice exposed to the pyrethroid pesticide deltamethrin in utero and through lactation exhibited several features of ADHD.
These included dysfunctional dopamine signalling in the brain, hyperactivity, working memory, attention deficits and impulsive-like behaviour.
These findings provide strong evidence, using data from animal models and humans, that exposure to pyrethroid pesticides, including deltamethrin, may be a risk factor for ADHD, said lead author Jason Richardson, associate professor in the Department of Environmental and Occupational Medicine at Rutgers Robert Wood Johnson Medical School.

"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 Richardson.
In the study, male mice were affected more than the female mice, similar to what is observed in children with ADHD.

The ADHD-like behaviours persisted in the mice through adulthood, even though the pesticide, considered to be less toxic and used on golf courses, in the home, and on gardens, lawns and vegetable crops, was no longer detected in their system.
Using data from the Centers for Disease Control, National Health and Nutrition Examination Survey (NHANES) the study analysed 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.
Young children and pregnant women may be more susceptible to pesticide exposure because their bodies do not metabolise the chemicals as quickly, researchers said.
The research is published in the Journal of the Federation of American Societies for Experimental Biology (FASEB).