SCIENTISTS have produced the first proof that genetic code faults play a key role in triggering attention deficit hyperactivity disorder.
This undermines theories that the fault lies with poor parenting or eating too many lollies.
About 50,000 Australian children are estimated to be taking stimulants to manage ADHD, which makes children restless, disruptive and easily distracted.
Experts say this level of drug use makes Australia the world’s third-highest consumer of such medicines on a per capita basis.
British researchers, who compared the DNA of 366 children with ADHD with the genetic code of more than 1000 unaffected counterparts, found children with the condition were more likely to have short lengths of their genetic code that were either duplicated or missing.
These faults, known as copy number variations (CNVs), were often found to be in the same region of the DNA code as similar faults previously linked to autism and schizophrenia.
The authors, led by experts from Cardiff University, said the findings suggested ADHD and autism, while separate conditions, might share a similar biological basis and that ADHD was a brain development disorder — not just a complicated medical term for bad behaviour.
The findings were published yesterday in the British medical journal The Lancet.
Lead author Anita Thapar said she hoped the study would “help overcome the stigma associated with ADHD . . . too often, people dismiss ADHD as being down to bad parenting or a 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,” Professor Thapar said.
Another author, Kate Langley, said that, as ADHD was probably caused by a variety of genes interacting with as yet unidentified environmental factors, it would not be possible to identify children with ADHD by screening them for the gene faults.
Alasdair Vance, professor of child and adolescent psychiatry at the Royal Children’s Hospital in Melbourne, said the research confirmed genetic links. “This is an important, elegant study that demonstrates the genetic contributions to ADHD.”