Cardiff University researchers report in The Lancet that they’ve found the first direct evidence that attention-deficit/hyperactivity disorder (ADHD) is, at least to some extent, a genetic condition. After analyzing the DNA of 366 children diagnosed with the disorder and 1,047 without the condition, they found 15 percent of the ADHD kids had small segments of their DNA duplicated or missing, compared to 7 percent in the control group.
“I’d say clearly there’s a genetic contribution,” says Dr. Ross. “But the relationship does not seem to be a simple one — rather, the factors influencing ADHD occurrence are polygenic (related to two or more genes) and there may well be some interaction with an environmental factor or factors that we haven’t yet discovered.”
Lead investigator professor Anita Thapar says she hopes the findings reduce the stigma associated with ADHD. “Too often, people dismiss ADHD as being down to bad parenting or poor diet,” she says. “Now we can say with confidence that ADHD is a genetic disease and that the brains of children with this condition develop differently to those of other children.”