Many children who have autistic traits are never diagnosed clinically, leading to them not receiving the support they need through educational or health services, a new study has said.
There has been a major increase in the incidence of autism over the last twenty years.
In recent studies these undiagnosed children have been included in estimates of how many children have autism spectrum disorder, or an ASD (which includes both autism and Asperger's syndrome).
Such studies have estimated that one in every hundred children has an ASD.
A study found that a large number of undiagnosed children displayed autistic traits: repetitive behaviours, impairments in social interaction, and difficulties with communication.
These traits were at levels comparable to the traits displayed by children who held a clinical diagnosis (all diagnosed between years one and twelve).
However, the undiagnosed children were not deemed eligible for extra support at school or by specialized health services.
"ASD diagnosis currently holds the key to unlocking intervention from school systems and health programs," lead researcher of the study, Ginny Russell, asked.
"Perhaps these resources should be extended and available for children who show autistic impairments but remain undiagnosed," Russell stated.
Russell points out that the study also shows that there is a gender bias in diagnosing children with Autistic Spectrum Disorders - boys are more likely to receive a diagnosis than girls, even when they display equally severe symptoms.
The findings have been published in a recent issue of the Journal of Child Psychology and Psychiatry.