On Jan. 29, 2015, a Rutgers University study suggests that pregnant women and young children are more susceptible to a commonly used pesticide which may alter the development of the brain’s dopamine system — responsible for emotional expression and cognitive function – and increase the risk of attention deficit hyperactivity disorder in children.

The research published in the Journal of the Federation of American Societies for Experimental Biology (FASEB), by Rutgers scientists and colleagues from Emory University, the University of Rochester Medical Center, and Wake Forest University discovered that mice exposed to the pyrethroid pesticide deltamethrin in utero and during breastfeeding exhibited several features of ADHD, including dysfunctional dopamine signaling in the brain, hyperactivity, working memory, attention deficits and impulsive-like behavior.

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, says lead author Jason Richardson, associate professor in the Department and Environmental and Occupational Medicine at Rutgers Robert Wood Johnson Medical School and a member of the Environmental and Occupational Health Sciences Institute (EOHSI).

Attention deficit hyperactivity disorder most often affects children, with an estimated 11 percent of children between the ages of 4-17– about 6.4 million – diagnosed as of 2011. Boys are three to four times more likely to be diagnosed than girls. While early symptoms, including an inability to sit still, pay attention and follow directions, begin between the ages of 3 to 6, diagnosis is usually made after the child starts attending school full time.

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.