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Autism signs & symptoms

What Are the Symptoms of Autism?

Last updated 24 October 2026 · 11 min read · By Sarah M., Support Coordinator
In short

Symptoms of autism fall into two areas: differences in social communication skills, and repetitive behaviour, intense or special interests, and sensory sensitivities or differences. Every autistic person shows these differently, and only a qualified clinician can assess autism.

This guide is for autistic people, families, carers and support workers. It covers early signs, signs by age and gender, behaviours, sensory experiences, checklists for reflection, and how the NDIS may help if you meet the access requirements.

Key points

  • The DSM-5-TR autism criteria cover two areas: social communication differences, and repetitive behaviour, special interests and sensory differences.
  • Early signs of autism usually become noticeable during the first 1-2 years of life, though some people are recognised later.
  • Autism can look different from person to person, and one sign alone does not mean someone is autistic.
  • Checklists are for reflection only, and a proper assessment by a qualified professional is needed for a diagnosis.
Symptoms of autism at a glance
Two main areasSocial communication differences; repetitive behaviour, special interests and sensory differences
When signs appearUsually noticeable during the first 1-2 years of life, though some people are recognised later
Where to startTalk to your GP about a proper assessment
Free helplineAutism Connect on 1300 308 699, open 8am to 7pm Monday to Friday
NDIS relevanceSupports may be funded if you meet the NDIS access requirements
Where to read moreRaising Children Network; Amaze Autism Connect

What are the symptoms of autism?

Autism is a difference in how a person communicates, takes in the world and relates to others. The word symptoms is used in diagnostic guides, but some autistic people prefer to talk about traits and features.

The two areas in the DSM-5-TR criteria are the starting point for assessment (Raising Children Network).

TermWhat it meansWhy it matters
Social communicationHow a person uses words, gestures, eye contact and shared attentionIt is one of the two areas in the criteria
Repetitive behaviourRepeated movements, words or routinesIt is part of the second area of the criteria
Special interestsIntense focus on a topic or activityThey are part of the second area of the criteria
Sensory differencesSensory sensitivities or differences, such as to sound, light or touchThey are part of the second area of the criteria
SpectrumThe wide range of ways autism appearsIt explains why support needs differ

Signs and symptoms of autism in the two areas

These traits of autism are examples only, and one person will usually show some but not all of them.

AreaWhat it can look likeExample
Social communicationDifferent use of eye contact, gestures or turn-taking in conversationPreferring to talk at length about a favourite topic
Social interactionDifferent ways of joining in with othersPreferring one-to-one time to large groups
Repetitive behaviourRepeating movements, phrases or routinesFollowing the same order each morning
Intense interestsStrong focus on a topic, object or activityCollecting facts about trains or animals
Sensory differencesStrong reactions to noise, lights, textures or smellsCovering ears in a busy shopping centre
  • Social autism is a search term, not a separate diagnosis; social communication differences are one of the two areas in the criteria.
  • Autism features and symptoms of ASD can look different at home, school or work, so notes from each setting can be useful to share with a clinician.
  • The Australian ADHD Guideline found children and adolescents with autism have a significantly higher risk of ADHD (high-risk groups); read about ADHD traits if the two overlap for you.

Early signs of autism in babies and toddlers

Early signs of autism usually become noticeable during the first 1-2 years of life (Raising Children Network).

Looking for NDIS support at home?

TQN Care support workers help with personal care, community access, respite and help around the home across Sydney, Melbourne and surrounding areas (NSW & VIC). Tell us what you need and we will call you back.

Make a referral →

Symptoms of autism by age and gender

Autism can look different at different ages, so these guides take each group in turn.

Autism symptoms checklist and autism spectrum disorder checklist

A checklist can help you gather your thoughts before an appointment, but it cannot diagnose anyone; only a qualified professional can assess this.

  • Do conversations, eye contact or reading other people’s feelings feel different from how others seem to manage them?
  • Do you or your child rely on routines and feel distressed when they change?
  • Are there intense interests that take up much of your time and attention?
  • Do sounds, lights, textures or crowds feel overwhelming or hard to ignore?
  • Have these differences been present since early life, even if they were not noticed?
  1. Write down examples. Note what you see at home, school or work and when it started.
  2. Book a GP or paediatrician visit. Bring your notes, reports from teachers and any developmental records.
  3. Ask about an assessment. Ask your GP or paediatrician how to arrange a proper autism assessment.
  4. Call Autism Connect for guidance. The free helpline on 1300 308 699 (Amaze) is open 8am to 7pm Monday to Friday.
  5. Keep your report. You may be asked for it when you look for support, including from the NDIS.

Read what autism is for the full definition before you begin.

ASD behaviour, meltdowns and stimming

These guides look at ASD behaviour that people often ask about.

Autism and argumentative behaviour

  • Arguing on its own cannot tell you whether someone is autistic.
  • Notes about when disagreements happen and what came before them can be useful to share with a clinician.
  • Talk to your GP if arguments are frequent or distressing for anyone involved.

Masking, burnout and autism features people miss

Some autistic people hide their differences to fit in.

Level 2 autism symptoms

  • Level 2 is a support level that can be recorded in an autism diagnosis; read different levels of autism for what each level means.
  • If a report gives a level, ask the clinician to explain what it means day to day.
  • Describe daily tasks you need help with, rather than relying on the level alone.

Autism recovery signs

  • Autism is a difference, not an illness to recover from, so it helps to think about goals rather than recovery.
  • Goals might include more comfort, new skills or stronger friendships, agreed with the autistic person.
  • Ask your therapist how they measure goals, and read autism therapy options.

Symptoms of autism and the NDIS

If you meet the NDIS access requirements, the NDIS may fund supports. A list of traits on its own is not an NDIS application.

  • Keep copies of reports from your clinician, school and therapists.
  • Write down the help you need with routines, appointments and getting out, so you can explain it clearly.
  • Read our guide to autism funding under the NDIS before you apply.
  • Browse TQN Care NDIS services to see support at home and in the community.

When to talk to a GP or specialist

You do not need to wait for a crisis to ask for help.

  • Your baby or toddler is not responding to their name, using gestures or sharing attention, or has lost skills they had.
  • A child, teenager or adult has long-standing differences in communication, routine or sensory responses affecting daily life.
  • Meltdowns, shutdowns, sleep problems or self-injury are becoming more frequent or unsafe.
  • Anxiety, low mood or exhaustion is getting worse; call Lifeline on 13 11 14 if you or someone you support needs to talk now.
  • You are a carer who feels overwhelmed or close to carer burnout; talk to your GP, or call Lifeline on 13 11 14 if you need to talk now.

If someone is in immediate danger, call 000.

Looking for NDIS support at home?

TQN Care support workers help with personal care, community access, respite and help around the home across Sydney, Melbourne and surrounding areas (NSW & VIC). Tell us what you need and we will call you back.

Make a referral →

Your next step

After an assessment, you can look at what daily support would help at home and in the community. At TQN Care, we provide support workers for personal care, community access, respite and help around the home across Sydney, Melbourne and surrounding areas (NSW & VIC). See our NDIS services, or make a referral and we will call you back.

SM
Sarah M., Support CoordinatorTQN Care is a registered NDIS provider supporting people across Sydney, Melbourne and surrounding areas (NSW & VIC).
Common questions

FAQs about symptoms of autism

When do signs of autism appear? +

Early signs usually become noticeable during the first 1-2 years of life. Some people are recognised later, in childhood, as teenagers or as adults. If you are unsure, talk to your GP.

What are the early signs of autism? +

Raising Children Network says autistic toddlers might not, or only sometimes, respond to their name, use gestures such as waving, or use eye contact to share interest. One sign alone does not mean autism. A clinician looks at everything.

What are the signs and symptoms of autism? +

They fall into two areas: differences in social communication skills, and repetitive behaviour, intense or special interests, and sensory sensitivities or differences. Each person is unique, and assessment by a qualified professional is needed.

What are the behaviours of autism? +

The criteria describe repetitive behaviour, intense or special interests, and sensory sensitivities or differences, alongside differences in social communication. In daily life this can include repeated movements or routines. A clinician looks at the whole picture, not one behaviour on its own.

How do I support autistic behaviour that feels challenging? +

Keep notes about what happens, when, and what came before it, then talk to your GP or therapist about support that suits the person. You can also call Autism Connect on 1300 308 699 for free information. If anyone is in immediate danger, call 000.

Can arguing be a sign of autism? +

Arguing on its own cannot tell you whether someone is autistic, and a proper assessment is needed for a diagnosis. If disagreements are frequent or distressing, keep notes about when they happen and talk to your GP about what might help.

References

Sources

  1. DSM-5 autism diagnosis — Raising Children Network
  2. Early signs of autism — Raising Children Network
  3. Autism Connect – national autism helpline — Amaze
  4. High-risk groups for ADHD — AADPA
  5. Autism — Raising Children Network
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