The Autism Spectrum

What is autism?

Autism is a complex neurodevelopmental disorder that affects a child’s ability to communicate and interact socially. It is described as a spectrum disorder, which means that it manifests itself across a wide range of behaviors from mild to severe, requiring varying degrees of support.
Although some studies have demonstrated early predictors of autism in infants as young as 6 months of age, children are typically diagnosed by the age of three. The symptoms of autism involve two major areas of development: social communication/interaction and restricted, repetitive patterns of behavior. Autism impacts a child’s abilities to:

  • Engage in reciprocal social interactions with others
  • Communicate with others in developmentally appropriate ways
  • Transition or adapt flexibly to changes in routine

While most of us possess some mild form of these characteristics, it is the excessive and persistent presence of these characteristics that substantially affect quality of life and dictate the need for supports. One of the hallmarks of autism is that the characteristics vary significantly among different children with autism. No two children with autism are the same.

The Autism Spectrum

Autism Spectrum Disorder (ASD) is categorized into three severity levels. This helps to determine the amount of support an individual with autism needs. For example, individuals with level 1 autism typically require fewer and less intensive supports compared to those with level 2 autism. Those with level 3 autism experience the greatest challenges in adaptive behavior and therefore require very substantial supports.

Below are the diagnostic criteria used by clinicians to determine whether an individual has autism.

Diagnostic Criteria for Autism Spectrum Disorder

A. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history (examples are illustrative, not exhaustive; see text):

  1. Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, or effect; to failure to initiate or respond to social interactions.
  2. Deficits in nonverbal communicative behaviors used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication.
  3. Deficits in developing, maintaining, and understand relationships, ranging, for example, from difficulties adjusting behavior to suit various social contexts; to difficulties in sharing imaginative play or in making friends; to absence of interest in peers.

B. Restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following, currently or by history (examples are illustrative, not exhaustive; see text):

  1. Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypes, lining up toys or flipping objects, echolalia, idiosyncratic phrases).
  2. Insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behavior (e.g., extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take same route or eat same food every day).
  3. Highly restricted, fixated interests that are abnormal in intensity or focus (e.g., strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interests).
  4. Hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment (e.g. apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).

C. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life).

D. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.

E. These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.

When diagnosing individuals with autism, clinicians must indicate the severity level of the disorder to help determine the amount of support a given individual needs, as follows:

  • Level 1 Autism—Needs support
  • Level 2 Autism—Needs substantial support
  • Level 3 Autism—Needs very substantial support

Severity is based on social communication impairments and restricted, repetitive patterns of behavior. Individuals with level 1 autism typically have higher adaptive skills and, therefore, require fewer and less intensive supports than those with level 2 autism. Individuals with level 3 autism experience the greatest challenges in adaptive behavior and, therefore, require very substantial supports.


Note: Individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder, or pervasive developmental disorder not otherwise specified should be given the diagnosis of autism spectrum disorder. Individuals who have marked deficits in social communication, but whose symptoms do not otherwise meet criteria for autism spectrum disorder, should be evaluated for social (pragmatic) communication disorder.

Specify if autism presents:

  • With or without accompanying intellectual impairment
  • With or without accompanying language impairment
  • Associated with a known medical or genetic condition or environmental factor
  • (Coding note: Use additional code to identify the associated medical or genetic condition.)
  • Associated with another neurodevelopmental, mental, or behavioral disorder
  • (Coding note: Use additional code[s] to identify the associated neurodevelopmental, mental, or behavioral disorder[s].
  • With catatonia (refer to the criteria for catatonia associated with another mental disorder)
  • (Coding note: Use additional code 293.89 catatonia associated with autism spectrum disorder to indicate the presence of the comorbid catatonia.)

Source: American Psychiatric Association’s Diagnostic and Statistical Manual, Fifth Edition (DSM-5).

How has “autism” terminology evolved over time?

Until 2013, “autism spectrum disorder” referred to an umbrella of disorders, including Autistic Disorder (classic autism), Asperger Syndrome, Pervasive Developmental Disorders – Not Otherwise Specified (PDD-NOS), Rett Syndrome, and Childhood Disintegrative Disorder. Since then, these disorders have been folded into the broad term Autism Spectrum Disorder, which ranges in severity of deficits based on level of supports required.

Cultural Changes

Some individuals with autism who have greater adaptive skills self-identify as having “Asperger Syndrome” or being an “aspie”. These are typically individuals who were diagnosed with “Asperger Syndrome” under the old diagnostic criteria from pre-2013. Some people with Asperger Syndrome may resist being called a person with Autism Spectrum Disorder (ASD), while others may embrace being called “autistic”.

Many members of the autism community, including self-advocates and well-regarded professionals, describe autism as a culture. As part of a growing neurodiversity movement, these individuals focus on initiatives that help society become more accepting of neurological diversity rather than focus on those that support efforts to “cure” them of their differences.

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