In a study published in Environmental Health, Cincinnati Children’s Hospital Medical Center researchers found a dose-response relationship between levels of a common household pesticide in children’s bodies, and ADHD symptoms and diagnoses.

“Due to concerns about adverse health consequences, the United States Environmental Protection Agency banned the two most commonly used organophosphate (organic compounds containing phosphorus) pesticides from residential use in 2000-2001,” stated a press release about the study. “The ban led to the increased use of pyrethroid pesticides, which are now the most commonly used pesticides for residential pest control and public health purposes. They also are used increasingly in agriculture.” Though considered by some to be a relatively “safer choice” pesticide overall, animal studies have linked pyrethroid exposure to “hyperactivity, impulsivity and abnormalities in the dopamine system in male mice,” stated the press release.

The researchers examined data from 687 children between the ages of 8 and 15 from the 2000-2001 US National Health and Nutrition Examination Survey, and looked for links between detected levels of urinary 3-PBA, a biomarker of exposure to pyrethroids, and reported diagnoses of ADHD or reported symptoms associated with ADHD.

“Children with urinary 3-PBA above the limit of detection (LOD) were twice as likely to have ADHD compared with those below the LOD,” reported the researchers. “Hyperactive-impulsive symptoms increased by 50% for every 10-fold increase in 3-PBA levels.”

“Given the growing use of pyrethroid pesticides, these results may be of considerable public health import,” the researchers concluded. For unclear reasons, the findings applied to boys but not to girls.

According to the US Environmental Protection Agency, “Pyrethrins and pyrethroids are insecticides included in over 3,500 registered products, many of which are used widely in and around households, including on pets, in mosquito control, and in agriculture.” The EPA is currently reevaluating their safety.

Wagner-Schuman, Melissa, Jason R. Richardson, Peggy Auinger, Joseph M. Braun, Bruce P. Lanphear, Jeffery N. Epstein, Kimberly Yolton, and Tanya E. Froehlich. “Association of Pyrethroid Pesticide Exposure with Attention-Deficit/hyperactivity Disorder in a Nationally Representative Sample of U.S. Children.” Environmental Health 14, no. 1 (May 28, 2015): 44. doi:10.1186/s12940-015-0030-y. (Full text)

Study links exposure to common pesticide with ADHD in boys (Cincinnati Children’s Hospital Medical Center press release on MedicalXpress, June 1, 2015)

Pyrethroids and Pyrethrins (US Environmental Protection Agency website, accessed June 10, 2015)