The unruly behavior of naughty kids has a medical name as in oppositional defiant disorder (ODD), doctors said.
And children who lash out at teachers or students have also been diagnosed with a condition termed intermittent explosive disorder (IED).
Psychologists are diagnosing ODD - characterised by persistent anti-authoritarian behaviour - at a greater rate than autism.
Child psychologist Lisa Good said the condition was real and created a lot of stress for parents, who couldn't understand why their child was mucking up.
Good, from the Psych Professionals in Brisbane, said she had diagnosed more children with ODD and conduct disorders over the past two years than autism, attention deficit hyperactivity disorder (ADHD) or anxiety.
"It is a lot more common. I would say it was the majority of my appointments this year," News.com.au quoted Good as saying.
But teachers don't know how to handle the aggressive students and governments do not recognise ODD for special classroom funding.
Queensland Teachers Union president Kevin Bates said unlike with autism, the Government offered no extra help to deal with ODD students, and often they ended up being suspended or excluded.
"It's all good and well to have a name for it, but we're not getting the resources," he said.
Experts estimate ODD could affect up to 10 per cent of children.