Attention-deficit hyperactivity disorder (ADHD) affects approximately 11 percent of children aged four to 17—that’s 6.4 million children diagnosed as of 2011. Boys are three to four times more likely to be diagnosed than girls. While there are certain hereditary factors that make some children more likely to develop ADHD more than others, environmental factors are also thought to play an important role.
In a recent study published in the Journal of the Federation of American Societies for Experimental Biology (FASEB), researchers discovered that exposure to the pyrethroid pesticide deltamethrin while in utero and through lactation was linked to the development of several features of ADHD in an animal model. Dysfunctional dopamine signaling in the brain, hyperactivity, attention deficits, and impulsive-like behavior were observed.
“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,” noted Jason Richardson, PhD.
Male mice were more affected than female mice in the study, similar to what is seen in children. The ADHD behaviors continued through adulthood even long after the pesticide exposure was no longer detected, highlighting the potential long-term effects of pesticide exposure.
The researchers then analyzed data from the Centers for Disease Control and found that children with higher levels of pyrethroid pesticide metabolites in their urine were more than twice as likely to be diagnosed with ADHD, supporting the findings of the animal study. The authors caution that young children and pregnant women are particularly susceptible to pesticide exposure. “We need to make sure these pesticides are being used correctly and not unduly expose those who may be at a higher risk,” said Richardson.