Schoolchildren who suffer from Autism Spectrum Disorders suffer from many mental health issues, especially anxiety and anger, says a new study from Manchester University.

"A good number of children on the autistic spectrum are performing well at school, which makes it very difficult for teachers to spot the degree of anxiety they suffer, especially as many consciously hide it or try to find strategies to deal with it unsupported," said Dr Judith Hebron, a specialist in autism research, according to a press release from Manchester University.

Hebron said that autistic children find it difficult to adapt to social structure like a school and are at increased risk of being bullied by other children. Also these children spend higher amounts of energy in trying to appear normal that often results in stress that leads to sudden outbursts of rage and anger. This display of destructive behavior then hampers their social wellbeing and affects their family life.

The study included 76 students; 23 of which were diagnosed with autism and another 21 with dyslexia.

In the study, children who were diagnosed with autism displayed higher levels of anxiety, depression, anger and disruptive behavior.

Anxiety was the most significant mental issue displayed in these children; 59 percent of the children demonstrated clinical levels of anxiety.

Researchers say that the study supports the idea that autistic children who attend mainstream schools may suffer from other mental difficulties as well.

"But as children experiencing chronic stress and anxiety are more likely to suffer from mental health problems in the future, it's vitally important we are aware of these issues and intervene early in order to minimise the risk. Many mainstream schools are doing excellent work in supporting and including young people on the autistic spectrum: there are ways to moderate their anxiety," Dr Hebron added.

According to estimates by the Centers for Disease Control and Prevention, 1 in 88 children and 1 in every 54 boys is born with autism in the U.S.

This article has been revised to reflect the following correction:
Earlier version of this article stated incorrectly that 59 percent of the children demonstrated clinical levels of anger. The most significant mental issue in these children is anxiety, not anger.