Health Library

Symptoms of Autism Spectrum Disorders

Autism spectrum disorder (ASD) symptoms vary. There are different mixes of symptoms. The severity of ASD can also vary. Most symptoms will appear before 3 years of age. Most show between 18 to 24 months.

ASD may cause a loss of some development that was already reached. It can also prevent or slow new development. Symptoms may be:

  • Social skills problems
  • Language and communication
  • Problem behaviors
  • Sensory processing problems

ASD can cause a wide range of behaviors such as:

  • Social skills problems, such as:
  • Little interaction or listening to others
  • No eye contact
  • Not imitating others
  • Wanting to play alone
  • Language and communication problems, such as:
  • Little or no speaking
  • No response to name
  • Repetitive language, words, and echo words
  • Use of language in unusual ways
  • Problem behaviors, such as:
  • Aggression
  • Repetitive behaviors—may spend hours with a single activity such as rocking or flapping a hand
  • Hyperactivity
  • Self-destructive behavior
  • Tantrums—can be with little or no prodding
  • Sensory processing problems, such as:
  • Staring at certain objects for a long time
  • Overreaction to small changes in their environment
  • Sensitivity to sound, smell, taste, sights, and touch
  • Feel pain from a light touch, but ignore more severe pain
  • Experience sounds as colors, and touches as sounds

Children and their families may benefit from early, intense treatment.


Autism spectrum disorder. National Institute of Mental Health website. Available at:

Autism spectrum disorders. EBSCO DynaMed website. Available at:

Signs and symptoms of autism spectrum disorders. Centers for Disease Control and Prevention website. Available at:

What are the signs of early autism? Autism Society website. Available at:

What are the early signs of autism? Healthy Children—American Academy of Pediatrics website. Available at: