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Autism Spectrum Disorder

How common is Autism Spectrum Disorder?

According to the Australian Advisory Board on Autism Spectrum Disorders, 1 in 160 Australian children aged between 6 and 12 years old has an Autism Spectrum Disorder (ASD), making it more common than many other childhood conditions.

There are gender differences in the occurrence of autism. Boys are four times more likely than girls to have Autistic disorder and boys are nine times more likely than girls to have Asperger’s disorder.

ASD describes a cluster of disorders, including:

  • Autistic disorder
  • Asperger’s disorder (also known as Asperger’s syndrome)
  • Pervasive developmental disorder not-otherwise-specified
  • Retts disorder
  • Childhood Disintegrative disorder.

ASD is caused by an irregularity of brain development, and is usually detected in early childhood and lasts throughout a person’s life. 

There is no known cause for ASD and currently no cure, but our understanding of ASD is continuing to grow with new research.

ASD will affect each person differently. Some will need lifelong support and services and others will be able to achieve academically and socially. Parents, families and carers can best support a person with ASD’s development by encouraging their strengths, skills and interests, which will help them to learn, communicate and socialise just like their friends and other people around them.

Signs of ASD

Although ASD is usually discovered in early childhood, for some people it may not be obvious until as late as adolescence, as is sometimes the case with Asperger’s disorder. People with Asperger’s disorder have average or higher-than-average abilities and an intellectual capacity within the normal range.

All people with ASD develop at different rates but it is fairly easy to observe development by checking if they are reaching important milestones and observing language or emotional or social behaviour. It is important to know that one person may only have a few characteristics, whereas another might have many.

Some will have unusual language patterns, such as speaking in a formal way with a monotone voice and limited use of non-verbal communication (such as hand gestures). Similar to Asperger’s disorder, people with ASD may have narrow interests or become easily fixated on a favourite topic. They may focus on order and routine or compulsive or repetitive behaviour. Epilepsy or seizures may develop in adolescents with ASD.

Types of ASD

While people with ASD may have overlapping symptoms, their occurrence varies enough that ASD is now diagnosed using a range of types:

  • Autistic disorder – diagnosed early between birth and 3 years of age. It is identified when children may experience developmental delays, problems with communication and social interactions, and/or unusual behaviours. They may also develop repetitive or particular interests.
  • Asperger’s disorder – diagnosed where children or teenagers develop typical early language and cognitive skills, however they experience difficulties in social interaction, delayed motor skills, particular interests and may have difficulty understanding the abstract use of language such as humour.
  • Retts disorder – diagnosed when children have initially healthy development through the first five months, and then between five and 30 months they may experience difficulty with developmental milestones and social interactions, reduced head growth and specific hand movements. Retts disorder is almost exclusively found in girls.
  • Childhood Disintegrative disorder – rare condition characterised by late onset of developmental delays that occurs around two to three years of age. It effects verbal communication, muscle control, social play and toileting skills.
  • Pervasive developmental disorders not otherwise specified – diagnosis used for children in the autistic spectrum who do not meet the full criteria of the other categories. These children may only have a small amount of identifiable symptoms which are not enough to determine a diagnosis of one of the four main disorders.


There is no medical test, such as a blood test or brain scan, for diagnosing ASD. A diagnosis is based on information provided about a child’s development, observing their behaviour, and the use of educational and psychological tests.

In Queensland, paediatricians, psychiatrists and neurologists assess and diagnose ASD. Input to diagnosis may be required from speech language pathologists, occupational therapists and psychologists.

When a child receives an ASD diagnosis, a number of things will happen. Options for treatment will be explored and a treatment plan will be developed. Information on services and support available in your community will also be provided. Children with ASD are more likely to have other problems such as sleep difficulties, restricted diet, epilepsy and tantrums. Discuss these issues with a doctor or paediatrician as these associated problems may be able to be successfully treated.

While there is currently no cure for ASD, there are many therapies an interventions that are beneficial. Every person with ASD will have different challenges and so, an individualised approach needs to be taken. A few of the common approaches are social skills training, cognitive behaviour therapy (help manage emotions, repetitive behaviours or obsessions) and speech and language therapy (help build conversation skills). Autism Queensland offers services to people with autism and their families. With early intervention, appropriate strategies, techniques and support can be put in place.

Helpful information

Creative Commons Attribution 3.0 Australia (CC BY 3.0)
Last updated:
14 June 2016

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