Diagnosing Autism Spectrum Disorder (ASD): What you need to know


Despite the abundance of information online and on social media, it can still be very confusing for families to understand whether an individual may meet the criteria of an "Autism Spectrum Disorder (ASD)" and how a diagnostic assessment is undertaken. As professionals with over a decade of experience in conducting diagnostic assessments, early intervention and ongoing evidence based therapies for individuals on the autism spectrum, we highly recommend seeking a professional opinion and a comprehensive assessment when it comes to a suspected ASD diagnosis.

The following presents a brief summary about ASD and what a comprehensive assessment may entail:

Q: What is Autism?

Autism is a ‘neurodevelopmental disorder’ which means it affects the functioning of the brain, it emerges early in one’s life (usually in early childhood) and it is likely to remain present throughout one’s life. The categorisation of autism has changed throughout the years, but the most recent classification in the DSM-5 (a frequently used publication for classifying mental disorders) suggests by the following:

  • Persistent delays in one’s social skills. This can include limited communication skills (verbal and nonverbal), a decreased interest, frequency or quality of social interactions with others, and/or a lack of understanding of relationships and appropriate behaviour in social situations.
  • Limited interest or flexibility in how they behave and think. This can include fixated interests or hobbies, difficulties with adjusting to change and a strong preference for sameness, and repetitiveness in what they say, act or do.

With its prevalence, Autism Spectrum Australia estimates that ASD affects 1 in 70 people in Australia. ASD is also 4 to 5 times more likely to affect males than females. However, more girls with ASD are being identified earlier nowadays given our increased understanding in how ASD presents very differently amongst females. For more information on ASD in girls, please click here. 

Q: What is the difference between Autism and Asperger’s?

Autism lies on a ‘spectrum’ as it was previously an umbrella term for a number of similar conditions. Asperger’s Syndrome (named after 'Hans Asperger', an Austrian doctor who wrote about autistic symptoms in the 1940s, was one such condition. It can be considered a milder form of autism; the impaired social skills and repetitive thinking and behaviour are still present, but the individual does not have the language delays and cognitive deficits (e.g. in learning or intelligence) that often occur with autism.

When DSM-5 was published in 2013, the decision was made to remove the term 'Asperger’s Syndrome' and other similar conditions (e.g. Pervasive developmental disorder- Not Otherwise Specified), and replace them with an umbrella term known as ‘Autism Spectrum Disorder’ (or ASD for short). As a result, the term 'Asperger’s Syndrome' has since been used less frequently by psychologists and other specialists.

Q: How is Autism diagnosed?

Autism or ASD is generally diagnosed by a psychologist who has had specialist training in specific diagnostic assessment tools, a developmental paediatrician or a psychiatrist. It can be detected as early as 18-24 months of age, however is usually officially diagnosed after 2 years of age.

At ACPC Psychology, children or adolescents suspected of having ASD (e.g. have social difficulties and/or significant problems in emotional regulation and/or repetitive/ restricted interests) will usually undergo a comprehensive assessment including clinical and diagnostic parent interviews, clinical child screening observations within a clinical or natural settings, standardised questionnaires completed by parents and teachers, and most importantly formal testing designed to evaluate an individual’s social interactive skills (e.g. the ADOS or Autism Diagnostic Observation Schedule).

It is important to note that the symptoms listed above have to be significant enough to affect a person’s daily functioning, whether it is at home, school or the community before a diagnosis would be considered.

A report will then be written up which collates the information and determines whether the child has ASD and/or other associated conditions that can co-occur such as Attention-Deficit/Hyperactivity Disorder (ADHD), Sensory Processing Disorder, or Anxiety. 

If an ASD diagnosis is made, a severity level will usually be provided for both the ‘social skills’ and the ‘repetitive behaviour’ criteria. The levels range from Level 1 to level 3 (mildly apparent symptoms to severely apparent symptoms), and indicate the severity of the symptoms and how much help and support the child is likely to need in their present and future development. 

Q: How does an Autism diagnosis benefit my child?

If you believe that your child meets some of the aforementioned criteria for ASD, here are some reasons why you may want to consider a diagnostic assessment for him or her:

  1. Being able to understand your child’s presentation better, including their strengths and weakness and learning how best to support their development. 
  2. It may help your child understand why they feel ‘different’ or have trouble getting along or understanding others.
  3. A diagnosis provides access to funding such as the National Disability insurance Scheme (NDIS), which can be used for psychological therapy services and other supports services to develop your child’s motor, language sensory, emotional, social and behavioural development.
  4. Your child’s school may also be able to provide for funding for additional learning support such as 1-on-1 time with aides or teachers in order to assist their occupational and social functioning at school. 

Should your child be assessed and a confirmation of ASD diagnosis is made, it is always important to remember that the DSM diagnosis of Autism does not define your awesome child! Every child is unique and this is even more true with ASD kids with different kinds of brains!

In the words of Temple Grandin (the most famous person with autism): "I warn parents, teachers and therapists to avoid getting locked into labels. They are not precise. I beg you: Do not allow a child or an adult to become defined by a DSM label."  

Written by: Jacky Au, Registered Psychologist (clinical psychology registrar) at ACPC Psychology


Temple Grandin & Richard Panek. The Autistic Brain: Helping Different Kinds of Brains Succeed

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