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Autism spectrum disorder: Overview

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Autism spectrum disorder1 (ASD) is the name for a range of similar conditions that affect a person's social interaction, communication, interests and behaviour. Every year researchers are unlocking more information on these disorders – helping children and their families to better manage the impact of the condition.

In children with ASD, the symptoms are present before three years of age, although a diagnosis can sometimes be made after the age of three.
There's no "cure" for ASD, but speech and language therapy, occupational therapy, educational support, plus a number of other interventions are available to help children and parents.

In 2015 there were 164,000 Australians with autism, a 42.1% increase from the 115,400 with the condition in 2012.2  (Changes in clinical diagnostic criteria implemented in 2013 and changes to questions identifying people with disabilities in the 2015 Survey of Disability, Ageing and Carers may have had some impact on the prevalence, relative to 2012.) 

Autism spectrum disorders are more commonly found in males than females. In 2015, males were 4.1 times more likely than females to have the condition, with prevalence rates of 1.1% and 0.3% respectively. There is variation in the prevalence of autism across age groups, peaking at ages 5 – 14 with a marked drop off commencing in the late teens.

School is an important social environment where children learn to interact with their peers, a task people with autism may find difficult. An appropriate school environment can provide opportunities to develop important social and life skills. Many children on the autism spectrum struggle socially, needing additional support throughout their education. 

In 2015, almost all children on the autism spectrum had some form of educational restriction (96.7%), including a small number who were unable to attend school because of their disability. Almost half (48%) of the children attended a special class in a mainstream school or a special school.

Of the young people (aged 5 to 20 years) with autism who were attending school or another educational institution, 83.7% reported experiencing difficulty at their place of learning. Of those experiencing difficulties, the main problems encountered were fitting in socially (63%), learning difficulties (60.2%) and communication difficulties (51.1%).

Signs and symptoms

People with ASD tend to have problems with social interaction and communication.

In early infancy, some children with ASD don’t babble or use other vocal sounds. Older children have problems using non-verbal behaviours to interact with others – for example, they have difficulty with eye contact, facial expressions, body language and gestures. They may give no or brief eye contact and ignore familiar or unfamiliar people.

Children with ASD may also lack awareness of and interest in other children. They’ll often either gravitate to older or younger children, rather than interacting with children of the same age. They tend to play alone.

They can find it hard to understand other people's emotions and feelings, and have difficulty starting conversations or taking part in them properly. Language development may be delayed, and a child with ASD won’t compensate their lack of language or delayed language skills by using gestures (body language) or facial expressions.

Children with ASD will tend to repeat words or phrases spoken by others (either immediately or later) without formulating their own language, or in parallel to developing their language skills. Some children don’t demonstrate imaginative or pretend play, while others will continually repeat the same pretend play.

Some children with ASD like to stick to the same routine and little changes may trigger tantrums. Some children may flap their hand or twist or flick their fingers when they’re excited or upset. Others may engage in repetitive activity, such as turning light switches on and off, opening and closing doors, or lining things up.

Children and young people with ASD frequently experience a range of cognitive (thinking), learning, emotional and behavioural problems. For example, they may also have attention deficit hyperactivity disorder (ADHD), anxiety, or depression.

About 70% of children with ASD have a non-verbal IQ below 70. Of these, 50% have a non-verbal IQ below 50. (In composite verbal and non-verbal IQ tests 8.9% of the standard population scores 70 and below.) Overall, up to 50% of people with "severe learning difficulties" have an ASD.

Getting a diagnosis

The main features of ASD – problems with social communication and interaction – can often be recognised during early childhood.

Some features of ASD may not become noticeable until a change of situation, such as when the child starts preschool or school. 

See your GP or maternal and child health nurse if you notice any of the signs and symptoms of ASD in your child, or if you're concerned about your child's development. It can also be helpful to discuss your concerns with your child's kindergarten or school.

If appropriate, your GP can refer you to a healthcare professional or team who specialise in diagnosing ASD, or someone who has access to such a team. 

The specialist or specialist team will make a more in-depth assessment, which should be started within three months of the referral.

If you're referred to an individual specialist, they may be a:

  • psychologist – a healthcare professional with a psychology degree, plus further training and qualifications in psychology 
  • psychiatrist – a medically qualified doctor with further training in psychiatry 
  • paediatrician – a doctor who specialises in treating children 
  • speech and language therapist – a specialist in recognising and treating communication problems 

Some local health authorities use multidisciplinary teams. These are a combination of specialists who work together to make an assessment.


A diagnosis of ASD is based on the range of features your child is showing. 

For most children:

  • information will be needed from your GP, kindergarten or school staff, plus speech and language and occupational therapists, about your child's development, health and behaviour 
  • a speech and language therapist, and often an occupational therapist, will carry out an assessment 
  • a detailed physical examination will need to be carried out to rule out possible physical causes of your child's symptoms, such as an underlying condition like neurofibromatosis or Down's Syndrome  
  • the assessment will include a check for any coexisting physical health conditions and mental health problems 

In addition, for some children:

  • you may be asked to attend a series of interviews so a detailed family history and the history of your child's development and behaviour can be drawn up 
  • your child may be asked to attend a series of appointments so specific skills and activities can be observed and assessed  

Once this process is complete, a diagnosis of ASD may be confirmed.

Caring for someone with ASD

Being a carer isn't an easy role. When you're busy responding to the needs of others, it can affect your emotional and physical energy, and make it easy to forget your own health and mental wellbeing. 
If you're caring for someone else, it's important to look after yourself and get as much help as possible. It's in your best interests and those of the person you care for. 

What causes ASD?

It is not known exactly why some children develop autism. The idea that vaccination caused autism was attractive to some people who wanted to find a clear cause. However, this idea arose from a few studies that were badly conducted and have since been proven wrong. Current research suggests that autism cannot be explained by a single cause, but is probably due to a combination of developmental, genetic and environmental factors.3

A number of high quality studies have compared the health of large numbers of vaccinated and unvaccinated children over many years. The largest study included 537,303 children born in Denmark and found that unvaccinated children were just as likely to develop autism as vaccinated children. 

When the results of this study were combined with the results of nine other studies to include medical information from nearly 1.5 million children living all around the world, researchers were able to confirm that vaccination could not be causing autism.

Seeing a GP is a great place to start if you are concerned about any health issues. Should your children display any symptoms your GP can provide assessment, information and treatment options.

1 Contains public sector information licensed under the Open Government Licence v3.0. 

2 4430.0 - Disability, Ageing and Carers, Australia: Summary of Findings, 2015

3 SARAH Collaboration. SARAH is funded by the Australian Government Department of Health.