Signs of autism and the road to diagnosis

Last updated 15 February 2023

Autism spectrum disorder (ASD) is a common developmental condition that may lead to communication and behavioural challenges in people with autism.

Key points

Autism is often diagnosed at a young age, typically between the ages of three and eight, but it is not uncommon to be diagnosed later
Signs of autism will vary depending on where a person sits on the autism spectrum
You may be able to access the National Disability Insurance Scheme (NDIS) for your child, or early intervention support to assist with developmental delays

The public perception of autism has changed over the years and it is now recognised that autism presents differently among individuals, and this is referred to as the autism spectrum.

Autism typically presents itself during early childhood, although some children will show very minor signs, while others may have communication, repetition and behavioural challenges.

If your child is on the autism spectrum, or you believe they are, it is important that you support them and nurture their development appropriately.

Diagnosing autism

If you have noticed any developmental delays or behaviours you are unsure about in your child, speak to your doctor.

Your General Practitioner (GP) or paediatrician will be able to answer any questions you may have about where your child sits compared to general developmental milestones and if the behaviours your child is displaying should be investigated further.

Your health practitioner will collect information including your family’s medical history, and your child’s medical and health history. A medical professional is also the only person who can make a diagnostic evaluation to determine if someone is on the autism spectrum.

That means you must either visit your GP, a paediatrician, a psychiatrist or psychologist, or a multidisciplinary team featuring various medical professionals that can assess someone with more complex medical conditions.

First, there will be an assessment of function that looks at how a child thinks, learns, communicates and interacts with others. By assessing their abilities and behaviour it can be determined if any developmental delays are present.

Next, a medical assessment will be required to ensure there are no other reasons for developmental delays. If there is no other cause, a diagnostic assessment will be done to observe for signs of autism – although there is the likelihood those signs will be presented themselves along the way.

Once these tests have been completed you will receive a written report containing the information collected, what this means and where to from here.

More information on the diagnosis of autism can be found at Autism Awareness Australia.

What are the signs of autism in children?

Some children don’t present any symptoms of autism, meaning it may be difficult to pick up on the need for diagnosis. But for others, there will be clear signs that are viewed as the more common, or traditional, signs of autism.

These signs may or may not present themselves together, and this is not a full list of behaviours for people with autism. The autism spectrum is varied and any number of possible behaviours and signs could occur.

It is recommended you seek professional advice from a healthcare professional if you notice any of the below signs in your child at these ages.

12 months

Does not smile or show affection, particularly to parents
Does not pay attention to new faces, or is frightened of new people
Limited or no eye contact, and does not follow moving objects with their eyes
Does not babble, laugh or form words
Does not turn their head when they try to locate a sound or someone approaches them
Does not crawl, cannot stand unsupported, and cannot push down on their legs when standing on a firm surface
Dislikes physical contact
Little or no response to their own name

24 months

Has not achieved the milestones they should have by 12-18 months
Very few or no meaningful two-word phrases; does not speak
Cannot walk on their own or with a walking aid like a toy
Does not imitate actions
Cannot follow simple instructions

36 months

Has not achieved the milestones they should have by 24 months
Has limited speech, cannot speak in short phrases
Does not understand simple instructions
Has little interest in socialising
Does not enjoy ‘make-believe’ play or using their imagination
Frequently falls or has difficulty with stairs

At any age

Is mute or has difficulty with communication
Avoids eye contact
Difficulty understanding feelings
Repetition of words/obsessive-compulsive behaviours
Resistance to changes in routine or surroundings
Restricted interests and/or behaviours
Children act out at school or behave differently with teachers and students
Unusual and intense reactions to sensory stimulation, e.g. sound, smell, taste, texture, light and colour
Difficulty picking up on social cues, such as tone of voice or body language, in others

Additionally, autism in girls may look different. Girls are often better at masking their behaviours, which means they may mimic others to blend in socially. We have more information in our article, ‘Recognising autism in boys and girls – what’s the difference?‘

Likewise, autism in adults is often different as the behaviours have gone unnoticed through childhood. You can learn more about it here in our article ‘Autism in adults: signs, diagnosis and treatment‘.

When should my child be tested?

Your child should be screened for developmental delays and disabilities at nine months, 18 months, 24 and 30 months. Additional screenings are to be performed if they are at higher risk of delays due to premature birth, low birth weight or relevant family history.

Screening specifically for autism should happen at 18 months and 24 months, with any additional screening for high risk children (for example, if other children in the family have autism).

Your regular doctor can health check your child, but any concerns requiring an assessment will be referred to a specialist or health practitioner with experience in diagnosing neurodevelopmental and behavioural conditions, such as developmental delays and autism.

What are the levels of autism?

While it is difficult to truly define autism, it is diagnosed across three different levels to better deliver appropriate supports. For a more in-depth read, take a look at ‘Understanding the different levels of autism‘.

There are different levels of autism, all requiring specific supports. Your child’s level of autism will be indicated when a diagnosis is reached.

Those diagnosed with Level 1 autism require supports such as behavioural therapy to assist in improving their social communication skills or picking up social cues such as body language, jokes and sarcasm. People with autism at this level may also find it difficult to switch between activities and face challenges with organisation and planning.

People with Level 2 autism require ‘substantial’ support. They experience challenges in verbal and non-verbal social communication skills, social impairments, inflexibility of behaviour, restricted or repetitive behaviours and difficulty coping with change. Occupational therapy is one recommended type of support.

Those diagnosed with Level 3 autism require ‘very substantial’ support. People with autism often have severe challenges in their verbal and non-verbal social communication skills, difficulty coping with change and restricted or repetitive behaviours. They may also show aggressive behaviours and more personalised therapies and supports are necessary.

What happens next?

If you have a confirmed autism diagnosis, your GP or relevant healthcare professional can provide additional information on what therapies or supports are beneficial. You can also contact the autism-specific organisations listed here for more details on navigating life with autism.

Depending on your level of autism and eligibility, you may also apply for supports through the National Disability Insurance Scheme (NDIS). If your child is under six years of age you may be able to receive early intervention support through the Early Childhood Early Intervention program.

This program aims to give children the best start to life by identifying the type and level of support they need, promoting inclusion in the community and providing opportunities to learn and grow.

To access supports through the NDIS from the age of seven, you are required to meet the NDIS eligibility criteria. People with an autism diagnosis are not automatically accepted into the NDIS.

For more information on the NDIS, take a look at ‘What is the NDIS‘ or explore th Disability Support Guide.

What more would you like to know? Tell us in the comment section below.