Signs and symptoms of autism spectrum disorder (ASD)

Learn the signs and symptoms of autism spectrum disorder (ASD).

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What are the signs and symptoms of ASD?

Every person with ASD is unique, so the timing and severity of the first signs and symptoms can vary widely. Some children with ASD show signs within the first few months of life. In others, symptoms may not become obvious until 24 months or later. Some children with ASD appear to develop normally until around 18 to 24 months of age and then stop gaining new skills and/or start losing skills.

During infancy (up to 12 months), a child may show symptoms that include:

  • Limited or no eye contact
  • No babbling
  • Appearing not to hear (no response to name when called)
  • Playing with toys in an unusual or limited manner
  • Showing more interest in objects instead of people
  • Starting language skills but then stopping or losing those skills
  • Showing repetitive movements with their fingers, hands, arms or head

Up to 2 years of age, there may be continuing symptoms from infancy. A child may also:

  • Focus only on certain interests
  • Be unable to have reciprocal social interactions
  • Move in unusual ways, such as tilting their head, flexing their fingers or hands, opening their mouth or sticking out their tongue
  • Have no interest in playing with other children
  • Repeat words or phrases without appearing to understand them
  • Have behavioural issues, including self-injury 
  • Have trouble controlling their emotions (tantrums)
  • Like to have things a certain way, such as always eating the same food

Possible signs of ASD at any age:

  • Avoids eye contact and prefers to be alone
  • Struggles with understanding other people’s feelings
  • Remains nonverbal or has delayed language development
  • Repeats words or phrases over and over (echolalia)
  • Gets upset by minor changes in routine or surroundings
  • Has highly restricted interests
  • Performs repetitive behaviours such as flapping, rocking or spinning
  • Has unusual and often intense reactions to sounds, smells, tastes, textures, lights and/or colours.

Should I get my child assessed?

You should get your child assessed for ASD if:

  • you have concerns
  • you notice any signs or symptoms
  • your child has a close relative with ASD (for example, if a brother or sister has ASD)

Normally, your health care provider will test your child first. You can help your health care provider understand the unusual behaviour you see by:

  • taking photographs
  • maintaining logs or diaries
  • capturing these behaviours on video

If there are concerns, then your health care provider should refer you to a specialist for more tests. A specialist is the best person to help diagnose your child.

How is ASD diagnosed?

There is no simple medical test for diagnosing ASD.

To diagnose a child with ASD, a healthcare professional observes the child’s levels of:

  • communication
  • behaviour
  • development

This could include the child’s:

  • verbal skills
  • mental abilities
  • how they relate to others
  • behaviours related to their interests and activities
  • repeated actions related to how they speak, move or use objects

To determine the severity of ASD, the healthcare professional observes the amount of difficulty the child has with:

  • social communication
  • restricted, repetitive behaviour

Medical professionals use the Diagnostic and Statistical Manual for Mental Disorders (DSM-5) to evaluate ASD.

If a health care provider thinks that your child may have ASD, get a referral for a diagnosis. A specialist will create a detailed description of your child's strengths and challenges. A team of health professionals may work together for this assessment.

Testing for ASD will also make sure that this is not a different condition. For instance, sometimes hearing loss can explain your child’s unresponsiveness in social situations or when their name is called.

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