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What are the symptoms of autism spectrum disorder (ASD)?

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The symptoms of one person with autism can be very different from the symptoms of another person with autism. Health care providers think of autism as a spectrum disorder—which means that there is a range of similar features in different people with the disorder.1

One person with autism may have mild symptoms, while another may have more serious symptoms, but they both have ASD.

Despite the range of possible symptoms, there are certain actions and behaviors that are common in ASD and could signal that a child is on the autism spectrum. Parents and caregivers who notice these "red flags" should speak to their child's health care provider about autism and screening the child for ASD.

In general, the main signs and symptoms of ASD relate to:

  • Communication and interactions with other people
  • Routines or repetitive behaviors, sometimes called stereotyped (pronounced STER-ee-uh-tahypt) behaviors

Red Flags for ASD

Communication

Note about these red flags:

Some of these red flags apply only at certain ages, so consider what is typical for other children your child's age.

Some red flags are more strongly associated with autism than others.

If your child shows any red flags for autism, talk to his or her health care provider right away.
  • Does not respond to his/her name by 12 months of age
  • Cannot explain what he/she wants
  • Doesn't follow directions
  • Seems to hear sometimes, but not other times
  • Doesn't point or wave "bye-bye"
  • Used to say a few words or babble, but now does not

Social Behavior

  • Doesn't smile when smiled at
  • Has poor eye contact
  • Seems to prefer to play alone
  • Gets things for him/herself only
  • Is very independent for his/her age
  • Seems to be in his/her "own world"
  • Seems to tune people out
  • Is not interested in other children
  • Doesn't point out interesting objects by 14 months of age
  • Doesn't like to play "peek-a-boo"
  • Doesn't try to attract his/her parent's attention

Stereotyped Behavior

  • Gets "stuck" doing the same things over and over and can't move on to other things
  • Shows unusual attachments to toys, objects, or routines (for example, always holding a string or having to put on socks before pants)
  • Spends a lot of time lining things up or putting things in a certain order
  • Repeats words or phrases (sometimes called echolalia [pronounced ek-oh-LEY-lee-uh])

Other Behavior

  • Doesn't play "make believe" or pretend by 18 months of age
  • Has odd movement patterns
  • Doesn't know how to play with toys
  • Does things "early" compared to other children
  • Walks on his/her toes
  • Doesn't like to climb on things such as stairs
  • Doesn't imitate silly faces
  • Seems to stare at nothing or wander around with no purpose
  • Throws intense or violent tantrums
  • Is overly active, uncooperative, or resistant
  • Seems overly sensitive to noise
  • Doesn't like to be swung or bounced on his/her parent's knee, etc.

Find age-specific milestones on the Centers for Disease Control and Prevention website Learn the Signs. Act Early. If your child does not meet these milestones, talk to his or her health care provider about screening for ASD.


  1. Diagnostic and Statistical Manual of Mental Disorders, 5th Edition. (2013). American Psychiatric Association: Washington, DC. [top]

Last Updated Date: 01/16/2014
Last Reviewed Date: 12/18/2013
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