23/01/2017 7:49 AM AEDT | Updated 23/01/2017 9:07 AM AEDT

Youngest Students Twice As Likely To Be Medicated For ADHD

More boys were medicated than girls.

Peter Cade via Getty Images
Boys were more likely to be medicated for ADHD than girls.

A quirk in a child's birth date will determine their liklihood of being medicated for ADHD, leading experts to call for Australia's diagnosis model to be thrown out.

A large-scale study from Curtin University found school children aged six to 10 were twice as likely to be medicated for ADHD if they were young -- born in the last month of the school intake -- as opposed to the first month of the intake.

The study of more than 311,000 Western Australian school children, published in the Medical Journal of Australia, also found also found boys were more likely to be medicated than girls.

Study leader Martin Whitely told The Huffington Post Australia the research confirmed large-scale studies in four other countries showing younger schoolchildren were more likely to be medicated for ADHD.

"It seems to be universal," Whitley said.

"Whether it's a high-prescribing place like the U.S. and Canada or a low-prescribing place like Taiwan and Australia, we're seeing the same pattern of younger children being medicated for ADHD.

"It indicates just a dodgy diagnosis."

Whitely said there was no medical reason why children who were young for their year would be prone to ADHD.

"It's mistaking age-related maturity, but that's not the only source of misdiagnosis," he said.

"Your odds of being diagnosed with ADHD are dependent on things like your postcode -- who the clinician is in your area, the attitude of your school teachers, whether your parents are believers or skeptics, it goes on.

"The diagnostic material for ADHD are all based on behavioural observation, like whether the child is losing their pens and pencils all the time, are easly distracted by extraneous stimuli, are figety in their seats. All kids at some point qualify for some of these behaviours and even extreme inattentive hyperactivity can be caused by poor eyesight, bullying, kids being too smart and bored, or not being smart enough and overwhelmed, as we;; as malnutrition, dehydration. Virtually anything can cause a child to be distracted and impulsive."

"The whole diagnosis model needs to be thrown out."