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?

ASD develops differently in each individual. The term spectrum is used because some signs of ASD can show together or in different combinations. Symptoms can be mild to severe.

The first signs of ASD can be seen in early childhood. ASD can be diagnosed by qualified health care providers in children as young as 12 months old. Parents often notice signs first. Children who have fewer or less obvious symptoms may not be diagnosed until they start school.

There are some signs that suggest a child should be tested for ASD. It is important to know that not all signs have to be present in order to test for ASD.

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

  • appearing not to hear
  • 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
  • developing delays in general that cause parents to be concerned, such as in movement, sleep and play behaviour

Your child may also not start babbling the way other babies tend to at this age.

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

  • avoid eye contact
  • be unable to form words
  • focus only on certain interests
  • move in unusual ways, such as:
    • tilting their head
    • tensing their arms
    • 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 trouble communicating, such as using unusual rhythm or tone to speak
  • have behavioural issues, including self-injury and trouble controlling their emotions (tantrums)
  • like to have things a certain way, such as always taking the same way to school or eating the same food

In addition, your child may not:

  • respond to their name
  • react in a common way to the environment in terms of:
    • pain
    • heat
    • lights
    • sounds
    • textures
  • look to others for social clues when deciding on a reaction
  • point and look, as children tend to do when they coordinate eye gaze and action

While someone with ASD can have difficulty with regular social communication and learning, they can also have extraordinary abilities. This can include abilities such as a:

  • talent for music and art
  • strong memory for certain facts or numbers

These skills are often unique and linked to a highly focused interest, like:

  • memorizing train schedules
  • knowing the flight paths of airlines
  • knowing the flag and capital of every country in the world

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. If there are concerns, then they should refer you to a specialist for more tests.

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

You and your health care provider should not wait to get your child tested if you have concerns. A specialist is the best person to help diagnose your child.

How is ASD diagnosed?

ASD is diagnosed based on the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (also known as the DSM-5).

People with ASD are evaluated on specific behaviours and their overall development. This could include:

  • 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

The amount of difficulty a person has with social communication and restricted, repetitive behaviour helps define the severity of ASD.

Every child develops differently. Even if your child has some ASD symptoms, they may only be diagnosed if symptoms reach a certain level of severity. This level considers behaviour that limits or interferes with their everyday functioning.

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. You may be asked a lot of questions about your child’s early development and the signs your child shows.

A diagnosis will describe what level of support is needed, such as:

  • some support
  • substantial support
  • very substantial support

The different categories used to describe the levels of ASD are meant to help understand individual needs. They are not to be used to decide if a person qualifies for support or services.

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