Autism is a developmental disorder that can affect a child’s basic skills, such as socialising or forming relationships, communication and using imagination. A child with autism may also have a limited range of interests.

The world around them will appear very different to a child with autism than the way it is seen by children without the condition.


Symptoms typically appear before a child is three years old and last throughout life. Children with autism can display a wide range of symptoms, which can vary in severity from mild to disabling. General symptoms that may be present to some degree in a child with autism include:

  • Difficulty with verbal communication, including problems using and understanding language.
  • Inability to participate in a conversation, even when the child has the ability to speak.
  • Difficulty with nonverbal communication, such as gestures and facial expressions.
  • Difficulty with social interaction, including relating to people and to his or her surroundings.
  • Inability to make friends and preferring to play alone.
  • Unusual ways of playing with toys and other objects, such as only lining them up a certain way.
  • Lack of imagination.
  • Difficulty adjusting to changes in routine or familiar surroundings, or an unreasonable insistence on following routines in detail.
  • Repetitive body movements, or patterns of behaviour, such as hand flapping, spinning and head banging.
  • Preoccupation with unusual objects or parts of objects.

People with a form of autism, called savantism, have exceptional skills in specific areas such as music, art, and numbers. People with savantism are able to perform these skills without lessons or practise.

What are the warning signs that a child may have autism?

Babies develop at their own pace, some more quickly than others. However, you should consider an evaluation for autism if any of the following apply:

  • Your child does not babble or coo by 12 months of age.
  • Your child does not gesture, such as point or wave, by 12 months of age.
  • Your child does not say single words by 16 months.
  • Your child does not say two-word phrases on his or her own (rather than just repeating what someone else says) by 24 months.
  • Your child has lost any language or social skills (at any age).

What causes autism?

The exact cause of autism is not known, but research has pointed to several possible factors, including genetics (heredity) and environmental factors.
Studies strongly suggest that some people have a genetic predisposition to autism, meaning that a susceptibility to develop the condition may be passed on from parents to children. Researchers are looking for clues about which genes contribute to this increased vulnerability. In some children, environmental factors may also play a role. Studies of people with autism have found abnormalities in several regions of the brain, which suggest that autism results from a disruption of early brain development while still in the uterus.
Other theories suggest:

  • The body’s immune system may inappropriately produce antibodies that attack the brains of children causing autism.
  • Abnormalities in brain structures cause autistic behaviour.
  • Children with autism have abnormal timing of the growth of their brains. Early in childhood, the brains of autistic children grow faster and larger than those of children without autism. Later, when the brains of children without autism get bigger and better organised, autistic children’s brains grow more slowly.