What Is Autism Spectrum Disorder?

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, which means that it impacts how a child develops. Autism begins in utero, although children with ASD might not be diagnosed until they are preschool- or even school-aged (or older), when signs of the disorder become more apparent.

Children with ASD have a combination of two kinds of behaviors: deficits in communication and social skills, and the presence of restricted or repetitive behaviors. It’s called a spectrum because individuals with the disorder may have a wide range of symptoms, cognitive abilities, language skills and behaviors.

Criteria for autism spectrum disorder

Signs of a deficit in communication and social skills may include, but are not limited to, a combination of the following:

In younger kids (under 3 years)

  • Failure to respond to their own name
  • Disinterest in giving, sharing or showing objects of interest
  • Aversion to displays of affection
  • Preference for solitary play

In older children

  • Difficulty carrying on a reciprocal or back-and-forth conversation
  • Lack of eye contact
  • Difficulty using and reading body language in others
  • Difficulty recognizing others’ emotions, responding appropriately to different social situations and understanding social relationships
  • Aversion to displays of affection
  • Preference for solitary play

Children with restricted or repetitive behaviors perform repetitive actions and rituals and can become fixated on minute details to the point of distraction. In addition, they may:

  • Become upset by minor changes in daily routine
  • Line, sort or organize toys or objects instead of playing with them
  • Show a consuming interest in a specific topic or object
  • Have unusual sensory sensitivities

To meet the criteria for ASD, a child’s symptoms in these two areas must be present in early childhood, though they may not become fully clear until later, when social demands exceed limited capacities. Alternatively, they may be clear early on and then masked later by learned strategies.

These symptoms must also cause clinically significant impairment in social, occupational, academic or other important areas of functioning.

In addition to the two required criteria to meet the diagnosis, children with autism spectrum disorder often have sensory issues and varying cognitive and verbal abilities.

Sensory problems: Many children with autism are unusually sensitive to sounds, lights, textures or smells. They may be overwhelmed by too much sensory input, avoiding, fleeing or melting down over things like bright lights, loud noises or commotion. Alternatively, they may seek more sensory input, which they may try to get by bumping into things and excessively touching and smelling things.

Verbal ability: Some children with autism don’t talk at all. Others talk in a stilted tone, or in an exaggerated “sing-song” or high-pitched voice. Highly verbal children with autism may monopolize conversations while showing little capacity for reciprocity or understanding what the other person wants or feels.

Autistic children may also repeat certain phrases without appearing to understand their significance, or possess what experts call “non-functional knowledge”— information they can recite, but not use to solve problems or carry on a conversation.

Children on the spectrum can also have medical problems and other mental health disorders, including anxiety, ADHD and depression, with symptoms that can be confused with autism.