No, the increase in ADHD over the past decade or so isn't just your imagination. It might even be linked to the food we eat every day. A recent study in the journal Pediatrics claims that children with high levels of exposure to a group of pesticides called organophosphates are nearly twice as likely to end up with ADHD as kids with minimal levels of the pesticides in their urine.
Reuters explains  that researchers analyzed the urine of 1,139 children between the ages of 8 and 15. The kids represented the average incidence of ADHD in the general population--1 in 10 met the criteria for the disorder. The results: For children with above-average levels of dimethyl triophosphate, a common breakdown product of organophosphates, the chance of having ADHD nearly doubled. And a 10-fold increase in one class of organophosphates increased the odds by over a half. So how do kids end up with organophosphates in their urine? A 2007 article from Beyond Pesticides  reports on the insecticide chlorpyrifos, an organophosphates manufactured by Dow AgroSciences:
Although chlorpyrifos was outlawed from residential use in 2001, it is still applied intensively on corn, wheat, and soy through a product called Lorsban. In Florida, 41% of the corn in 2004 had been treated with chlorpyrifos, according to a report by the National Agriculture Statistical Service. A study led by an Emory University researcher found that chlorpyrifos can enter children’s bodies through dietary exposure. The foods that are treated with chlorpyrifos—corn, wheat, and soy—are used in a variety of processed foods.
But exposure to these pesticides isn't inevitable. In the Emory University study, organophosphate levels dropped to nearly undetectable levels when children were put on an organic diet. Kids living near farms that use the pesticides, however, are out of luck. All the more reason to ramp up organic farming.