ADHD: A Possible Pesticide Pitfall

ADHD in young boys linked to pyrethroid pesticides, which are often used in bug spray

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Pesticides are used to keep bugs away and make life easier, but they might be making life harder for some children.

A new study tied higher exposure to a type of pesticide found commonly in bug spray to an increased risk of attention deficit hyperactivity disorder (ADHD) in young boys.

“Given the growing use of pyrethroid pesticides and the perception that they may represent a safe alternative, our findings may be of considerable public health importance," said lead author Tanya E. Froehlich, MD, of the Cincinnati Children’s Hospital Medical Center, in a news release.

According to these study authors, pyrethroid pesticides, or substances used to kill pests, are often considered "safer" and are now the most commonly used type of pesticides for both residential and public health uses.

Dr. Froehlich and team wanted to see whether there was a link between pyrethroid pesticides and ADHD, which they explained has been tied to environmental risk factors in past research.

ADHD is a common childhood disorder marked by issues like trouble paying attention, controlling behavior and staying focused. According to the National Institute of Mental Health, boys have a four times higher risk of ADHD than girls.

Dr. Froehlich and team looked at data from the 2001 to 2002 National Health and Nutrition Examination Survey to identify 687 children between the ages of 8 and 15. They studied urine samples from the participants to test for pyrethroid pesticides.

Of the study participants, 14.6 percent had ADHD, Dr. Froehlich and colleagues found. They determined this by looking at symptoms present in a diagnostic interview with the children or by a past diagnosis.

Only 21.1 percent of the children studied did not have pyrethroid pesticides in their urine. The remaining children did have detectable levels of pesticides in their urine. The children with pesticides in their urine were likely exposed to more of these pesticides.

Sixteen percent of those with pesticides in their urine had ADHD, compared to 9.6 percent of those without the pesticides. According to the study authors, this accounted for an ADHD risk that was around twice as high among those who were more exposed to the pesticides.

Dr. Froehlich and team also saw evidence that as the level of pyrethroid detected in the urine increased, so did hyperactivity in the patient.

This link between the pesticides and ADHD seemed to only be present in boys, not girls.

Dr. Froehlich and team noted that the study depended on only one urine sample from each patient. Several samples over time would likely provide more accurate data on the levels of pesticides the children were exposed to.

Most commercial bug sprays include active ingredient information on their labels.

This study was published online May 28 in the journal Environmental Health.

One of the study authors served as a consultant to a number of groups, such as the California Department of Toxic Substance Disease Control and the US Environmental Protection Agency. The National Institutes of Health and Cincinnati Children’s Hospital Medical Center funded this research.

Review Date: 
June 3, 2015
Last Updated:
June 8, 2015