Genetic basis for ADHD discovered

They found children with the condition, thought to affect one in 50, are more likely to carry particularly faulty sections of genetic code than those without it.

Anita Thapar, professor of child and adolescent psychiatry, said: "This is really exciting because it gives us the first genetic link to ADHD.

"We hope that these findings will help overcome the stigma associated with ADHD. Too often, people dismiss ADHD as being down to bad parenting or poor diet.

"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."

Thapar and her colleagues found that children with ADHD were twice as likely as others to have small genetic segments of their DNA duplicated or missing.

The research, published in The Lancet, also "suggests there may be a shared biological basis" for ADHD and autism.

Thapar added she hoped attitudes to ADHD would now change as they had done for autism: "Some years ago people were saying that autism was caused by 'refrigerator parents'. That has changed and hopefully it will change for ADHD too."

But she said the research was unlikely to lead to a genetic test for ADHD as there were too many other genetic and environmental factors at play.

Cerebra, the national charity for children with brain injuries and neurological conditions, welcomed the report. A spokesman said: "We do so on the grounds that it substantiates Cerebra’s long held view that ADHD is no less worthy a condition for support than those neurological disorders that have long been held to be physiological or genetic in nature.

"To assume a familial or parenting cause would be inappropriately judgmental in our view. This report suggests that it would not only be judgmental but erroneous. Whatever the cause, it is Cerebra’s view that ADHD, along with every other of the myriad neurological conditions should be addressed and supported on its own intrinsic merits."