It’s estimated that 2.5 percent of adults and 5 percent of children in the United States have Attention-Deficit/Hyperactivity Disorder. The condition is often spotted in school-age children with symptoms including distractibility, fidgeting and frequent daydreaming.
While causes for the condition are still unknown and current thought points to a genetic component, a new Rutgers study published in the Journal of the Federation of American Societies for Experimental Biology has discovered a possible link between the pyrethroid pesticide deltamethrin and ADHD. The researchers found that mice exposed to the pesticide in utero and during breastfeeding demonstrated hyperactivity, attention deficits, dysfunctional dopamine signaling in the brain and impulsive behavior, which are often seen in those with ADHD. The study’s lead author Jason Richardson says that based on the findings, exposure to pyrethroid pesticides like deltamethrin may be a risk factor for ADHD.
In addition to the findings in mice, the researchers also looked at health questionnaires and urine samples for 2,123 children and adolescents, and found that those with higher levels of pyrethroid pesticide metabolite in their urine were more than twice as likely to be diagnosed with the condition.
According to Sonya Lunder, senior analyst at the Environmental Working Group, there are very few studies of the effects of pyrethroids in people and we need more.
“Independent studies by government agencies and academic researchers are vital to uncovering the effects of pesticides and environmental contaminants on children’s health,” Lunder says. “Unlike other chemicals, every pesticide undergoes a series of toxicity studies before it is approved for the market. The 1996 Food Quality Protection Act requires that companies study the effect of their pesticide on the developing brain and nervous system. However independent observational studies of children and experiments like the Rutgers pyrethroid study, show that these pesticides may not be safe for children.”
Pyrethroids are commonly used in the home, agriculture and on pets as a less toxic alternative to organochlorine and organophosphate insecticides.
“There is no doubt that OCs and OPs are highly toxic to people and that is why those two families of insecticides are being phased out,” she says. “Pyrethroids are definitely less toxic, and that is why they are used in mosquito-repellent clothing and for mosquito abatement in residential areas (not deltamethrin, but related chemicals). They are also used in household pest treatments.”
For those concerned about pesticide exposure, Lunder suggests buying organic produce and packaged foods and avoiding using pesticides in and around the house whenever possible. Research the least toxic treatments for pets, lawn and garden pests and household infestations, she says.
“EWG’s annual Shopper’s Guide to Pesticides in Produce provides information about the amounts of pesticide residues on common fruits and vegetables,” says Lunder. “People are probably not aware that two-thirds of grocery store produce has residues of pesticide on them, even after they are washed and in some cases peeled before testing. Children generally have higher exposures to pesticides than adults because their small size means that they eat more food than adults, and because they spend more time playing on the floor and putting things that aren’t food in their mouths.”