In most cases, the symptoms of autism are detectable using certain screening tools on children 18 months old. However, parents and experts in autism treatment usually become aware of the symptoms before this time. In general, a formal diagnosis of autism can be verified. The medical specialist will rule out other disorders and use tests specific to autism and decide where a formal diagnosis of autism, autism spectrum disorder, or another disorder is appropriate.

There are a number of things that parents, teachers, and others who care for children can look for to determine if a child needs to be evaluated for autism. The following symptoms may be signs of autism and indicate that a child should be evaluated for autism or related communication disorders.

  • The child has poor eye contact.
  • Does not point or wave bye-bye.
  • Does not smile when smiled at.
  • Language skills or speech problems:
    • Language skills or speech are delayed.
    • The child does not respond to his/her name.
    • Cannot explain what he/she wants.
    • The child used to say a few words or babble, but now he/she does not.
  • The child has problems following directions:
    • Does not follow directions.
    • At times the child seems to be deaf.
    • Seems to hear sometimes but not other times.
  • The child has problems playing with toys:
    • Does not know how to play with toys.
    • Gets "stuck" on things over and over and can't move on to other activities.
    • Shows unusual attachments to toys, inanimate objects, or schedules.
  • The child seems to have problems playing with other children:
    • Prefers to play alone.
    • Seems to be in his/her "own world".
    • Seems to tune people out.
    • Is not interested in other children.
    • Gets things for himself/herself only.
    • Spends a lot of time lining things up or putting things in a certain order.
  • The child has odd movement patterns, for example:
    • Walks on his/her toes.
    • Flaps his/her hands or fingers in unusual ways.
    • Rocking and circling movements.
  • Throws intense or violent tantrums.
  • Hyperactive, uncooperative, or oppositional.
  • Does things "early" compared to other children.
  • Very independent for his/her age.