Organophosphate pesticides—commonly used on fruits and vegetables (and also for indoor pest control)—could increase the risk of attention-deficit/hyperactivity disorder (ADHD) in children, according to a new study in the journal Pediatrics. Using urine samples, researchers tested more than 1,100 children for breakdown products of organophosphate pesticides and found that those with the highest levels of dimethyl thiophosphate (the most common compound) were twice as likely to have ADHD as children with nearly undetectable levels.
“Because this was an observational study, we can’t say that exposure to organophosphates causes ADHD,” says study co-author Marc Weisskopf, Ph.D., Sc.D., of Harvard School of Public Health. But the possibility is plausible given that organophosphates target the nervous system (they kill insects by disrupting their brains and nervous systems) and past research has linked organophosphates with hyperactivity and cognitive defects in laboratory animals. While this study doesn’t definitively link organophosphates to ADHD, says Weisskopf, he recommends washing fruits and vegetables well to remove some of the pesticide residues, and buying organic.