What are Autism Spectrum Disorders?

Autism Spectrum Disorders (ASDs) are characterized by difficulties in social interaction, verbal and non-verbal communication, a restricted repertoire of activities and interests, and repetitive and stereotyped behaviour. Some people with ASD may also be over- or under-sensitive to sensory stimuli (sound, touch, taste, smell and visual). For many people with an ASD the world is a confusing place. ASDs are currently diagnosed according to criteria detailed in the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5). Previous subcategories in the previous editions of the DSM (DSM IV-TR) included Autistic Disorder (AD), Asperger's Disorder (AspD) and Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS).

Key facts

  • Young children with an ASD may display a lack of or reduced eye contact, emotional expression, responding when called by their name, joint attention and imitation. This can lead to difficulty in learning social routines (clapping, waving, peek-a-boo), delayed or atypical language development, under-developed play skills and sometimes unusual sensory behaviours (such as mouthing, aversion to touch or odd body movements).
  • These behaviours usually emerge very gradually, sometimes not until the second year of life.
  • ASDs are difficult to diagnose as there are no obvious physical or biological signs and no simple screening tests, such as a blood test. A diagnosis can only be based on the child/person's developmental history and observation of behaviour.
  • Current diagnostic tools allow a trained professional to reliably diagnose ASD as early as 18 months of age. Work is continuing to develop tools for an even earlier diagnosis.
  • ASDs are lifelong conditions and there is no known cure.
  • ASDs are approximately 3-4 times more common in males than in females.


As late as the 1990s autism was believed to be a 'rare' condition, affecting about 4 children in every 10,000. The increase to the current prevalence of 1-2% of children is due to the inclusion of AD, AspD and PDD-NOS in the same spectrum of disorders, the way children are diagnosed and a 'real' increase in the number of children affected by the disorder, the cause of which is unknown.


The underlying physiological causes of ASDs are currently not known. However, there is little doubt as to their genetic basis which causes changes in the pattern of brain development and function. Previous research has shown that ASDs are NOT caused by inadequate parenting, vaccinations or other medical interventions. Being a genetic condition means that ASDs tend to run in families and there is an increased chance (about 20%) of having another child with an ASD if there is already a child with an ASD in the family. ASDs are often associated with other conditions, including Fragile-X Syndrome, ADHD and/or developmental delay/intellectual disability.


The only treatment for ASDs shown to be consistently effective is early intensive behavioural interventions (EIBI), which is only possible when a diagnosis occurs early in the child's life. OTARC has been researching early identification and diagnosis and has been instrumental in establishing the Government-funded Victorian Autism Specific Early Learning and Care Centre (ASELCC) which provides early intervention services for preschool children with ASD and their families.

EIBI seeks to address the child's behavioural, social and communication difficulties with various programs, the most effective of which include some form of Applied Behavioural Analysis (ABA). The Early Start Denver Model is one of these programs, and this is the method of intervention implemented at the Victorian ASELCC.

Apart from early intervention, people with an ASD and their families usually need lifelong support, including educational, social communication, speech and language pathology and psychiatric support.

For more information about ASDs and resources for individuals and families affected by Autism Spectrum Disorders, visit the websites of