Is There a Link Between ADHD and Pesticides?

A possible link between attention deficit hyperactive disorder (ADHD) and pesticides surfaced in a Harvard University study published in 2010. The research found children diagnosed with ADHD had higher levels of an organophosphate pesticide metabolite than children without the disorder. Scientists who worked on the study suggested continued research to determine if a causal link can be made between ADHD and pesticides.

The study examined 1,139 children between eight and 15 years old, including 119 youngsters who had been diagnosed with ADHD. Researchers used prior studies on the topic and interviews with parents, along with measuring the levels of pesticide metabolites in the urine of study participants. They discovered that children with higher than average pesticide levels in the urine were twice as likely to have ADHD when compared to children with average or no measurable levels.

The 2010 study bolstered results from earlier research that discovered a possible link between ADHD and pesticides in the children of Mexican-American farm workers. The more recent research tested children from the general population instead of selected participants, and measured for six pesticide metabolites, including organophosphate residue. Organophosphate pesticide represents almost three-fourths of the pesticide used in the United States. It is also used by farmers in other countries.

This insecticide kills pests that threaten to destroy agricultural crops. Prolonged exposure to high levels of the chemical may disrupt signals in the central nervous system in insects and people. It is estimated that more than a billion pounds of chemicals are used each year in the U.S. agricultural industry.

After the study linking ADHD and pesticides was published, health experts recommended buying organic fruit and vegetables. In the alternative, produce should be washed and scrubbed before eating, especially celery, strawberries, and peaches, which typically test high for pesticides. Washing produce with soap is not recommended because chemicals in detergents might also be harmful.

There is no definitive cause of ADHD, a common disorder that affects millions of children. Children with the disorder usually have trouble concentrating, are unable to pay attention, and might be overactive. Their behavioral problems commonly disrupt their school performance, social interaction, and family life. Many children with ADHD take medication to control their symptoms.

Exposure to pesticides might come from eating fresh or frozen fruit and vegetables contaminated with chemicals. Those who work with pesticides face a greater risk of exposure when inhaling mist from spraying operations or from absorption through the skin. Exposure to large amounts of pesticide can cause seizures, paralysis, nausea, and vomiting.

People exposed to pesticides over a long period of time might experience memory problems, depression, and fatigue. They may also become irritable and depressed. The potential link between ADHD and pesticides might lead to stronger protective measures to reduce pesticide exposure.