Small levels of pesticides found on many foods may double a child's risk of ADHD, researchers say

Children with higher than average levels of pesticide metabolites were up to twice as likely to have ADHD as those with undetectable levels of pesticide metabolites, find Dr Marc Weisskopf, associate professor of environmental health and epidemiology at Harvard School of Public Health, and colleagues.

"This raises concerns that ubiquitous pesticides may be contributing to the national burden of ADHD, which already is quite high," Weisskopf tells us.
Weisskopf notes that his study is designed to detect a possible risk but is not able to prove that one thing caused another. For example, the data could be taken to mean that children with ADHD somehow behave in ways that increases their exposure to pesticides. While that appears counterintuitive, further studies are needed to test whether pesticides truly contribute to ADHD.
I hope they get on and find out which way round it is so that something can be done if necessary. It could be that we tend to eat a lot more food generally (we are more likely to be overweight due to self-medication with food, especially carbohydrates) or that a subset of us have metabolic abnormalities (a few metabolism-related genes have been linked to ADHD already) that explain why they're more detectable in our urine. Otherwise something had better be done, including testing new pesticides for long-term effects like this before they're introduced to the market.