Signs and Symptoms

The symptoms and characteristics of autism can occur in a variety of combinations, from mild to severe. While autism is defined by a certain set of behaviors, children and adults can exhibit any combination of the behaviors with varying degrees of severity. A child with classic autism may not speak at all, while a child with PDD-NOS or Asperger’s may have a lot of language, but still have difficulty with communication.

Lack of Communication Skills

  • Lack of or delay in developing language
  • Loss of previously developed language
  • Repeats words in place of language (called echolalia)
  • Leads people by the hand in place of asking verbally

Difficulty Relating to Others

  • Lack of eye contact
  • Lack of interest in other children and what other children are doing
  • Lack of response to verbal requests
  • No response when name is called
  • Little or no spontaneous or make believe play
  • Avoidance of physical contact
  • Indifference to others distress or pain

Unusual Behaviors

  • Self-stimulation, spinning, rocking, hand flapping, etc.
  • Inappropriate laughter or tantrums for no apparent reason
  • Inappropriate attachment to objects
  • Can exhibit obsessive compulsive behaviors
  • Repetitive play for extended periods of time
  • Insistence on routine and sameness
  • Difficulty dealing with interruption of routine schedule and change
  • Possible self injury behavior

Differences in Infant Behavior


  • Infants without autism may study mother’s face; infants with autism may avoid eye contact
  • Infants without autism are easily stimulated by sounds; infants with autism may seem deaf
  • Infants without autism keep adding to vocabulary and expanding grammatical usage; infants with autism may start developing language, then abruptly stop talking altogether
  • Infants without autism wave hi & bye; infants with autism may not wave

Social Relationships

  • Infants without autism cry when mother leaves the room and are anxious with strangers; infants with autism may act as if they are unaware of the coming and going of others
  • Infants without autism get upset or angry when frustrated; infants with autism may physically attack and injure others without provocation
  • Infants without autism recognize familiar faces and smile; infants with autism may be inaccessible, as if in a shell
  • Infants without autism try to gain joint attention of parent or caregiver to “show” them things; infants with autism may not try to “show” parent or caregiver things

Interaction with Environment

  • Infants without autism move from one engrossing object or activity to another; infants with autism may remain fixated on a single item or activity
  • Infants without autism use purposeful actions to reach or acquire objects; infants with autism may practice repetitive actions like rocking or hand-flapping
  • Infants without autism explore and play with toys; infants with autism may sniff or lick toys
  • IInfants without autism seek pleasure and avoid pain, react when harmed; infants with autism may show little or no sensitivity to pain, and engage in self-mutiliation or seem to overreact to touch
  • Infants without autism point at objects and sounds; infants with autism may not point at objects or sounds

Infants with autism will not always exhibit every symptom of autism – usually there will be a marked absence of the typical milestones with some combination of the autistic traits.

Sources: Autism Society,