Different Levels of Autism

Vilma Ruddock
There are different types of autism

The functioning level of a person with an autism spectrum disorder (ASD) diagnosis depends on the severity of his/her symptoms, dysfunctions and impairments in communication, and behavioral and social skills. Learning how psychologists and other medical specialists evaluate an individual to diagnose autism and assign a level of function can help you understand and manage this complex disorder.

Autism Functioning Levels

In the past, specialists assigned one of five forms of autism to a child after an evaluation. However, according to the National Institute of Mental Health, based on current knowledge:

  • Autism is a spectrum (range) of dysfunctions and deficits within a single disorder rather than a group of discrete diagnoses.
  • Using specific diagnostic criteria, a child's or adult's functional level of autism is graded from mild to severe based on his/her developmental impairments and ability to function and learn:
    • At one end of the spectrum are children and adults who cannot function in society due to their deficits.
    • At the other end are those "quirky" people who can lead independent and successful lives.

The designated functioning level defines where a child or adult falls on the autism spectrum and how well he or she can exist independently.

Making the Diagnosis

Developmental game

Signs of autism become evident in early childhood, usually before age three. Healthcare professionals use standardized tests to diagnose autism as well as to determine the functional severity of the disorder.

The 2013 fifth edition of the American Psychiatric Association's (APA) Diagnostic Manual of Mental Disorders (DSM-5) requires two sets of criteria to make the diagnosis of autism. You can download the DSM-5 autism factsheet from the APA website. The following are the two DSM-5 diagnostic functional criteria:

  1. Deficits in communication and social interactions, including:
    • Impaired use of language
    • Lack of eye contact and engagement with others
    • Impairment in use of and understanding of body language and facial expressions
    • Unusual response to show of emotions or affection
    • A lack of empathy towards, interest in, and connection with other people, and maintaining relationships
  2. Restricted interests and repetitive behaviors, including:
    • Engagement in repetitive behaviors, such as rocking the body and hand flapping
    • Repetition of words, phrases, or sentences, and robotic or sing-song speech pattern
    • Compulsive arrangement of toys and other objects
    • Unusual interests and a fixed engagement in an area of interest or hobby
    • Marked discomfort with a change in routines
    • Unusual reaction to visual and other stimuli such as sounds, smells, textures, and temperature

Assigning a Functioning Level

At the completion of the child's in-depth testing and assessment, specialists assign one of three autism functioning levels from mild to severe based on DSM-5 criteria for this assignment. A Centers for Disease Control and Prevention (CDC) factsheet gives an example of rating various areas of function, such as intelligence and social and communication skills. The following sections summarize the DSM-5 three levels of autism as outlined by Autism Speaks.

Level 3 or Low-Functioning Autism

Individuals with level 3 or low-functioning autism are on the most severe end of the spectrum. Children and adults need significant support, and adults with autism might not be able to live independently. The following dysfunctions severely affect a child's or adult's ability to function at school, home, or work, or to have normal social interactions and relationships.

Severe Deficits in Verbal Communication

Sad boy

Many of the people diagnosed with low-functioning autism are non-verbal. Those who are verbal have great difficulty using words to communicate. The CDC factsheet cited above notes that about 40 percent of children on the autism spectrum are non-verbal. These children cannot use spoken words in their interactions with others. They can mis-interpret verbal and non-verbal cues.

Impaired Mental or Cognitive Functioning

Some individuals with severe autism might also have another behavioral or mental disorder. Cognitive functioning is diminished, and some people have an IQ below 70. This presents problems with adaptive behaviors such as self-care and communication.

Behavioral Extremes

With level 3 autism, there is extreme fixation on a few, often atypical, behaviors to the exclusion of others. There is marked repetition of the restricted behaviors, and this can severely affect day-to-day activities and engagement with others.

If forced to deal with a change in routine, an individual might become upset or angry. In addition, inability to communicate and sensory overload can lead to frustration and disruptive or harmful behaviors towards himself and others.

Impairment in Social Skills

Someone with severe autism has extreme difficulty interacting with other people. The child or adult might completely exclude interacting with others and prefer to be alone. The individual may not be aware of what others are saying or doing, and it may take significant effort to gain his or her attention.

Level 2 or Moderate-Functioning Autism

Mother helps her autistic son with schoolwork

People with level 2 or moderate-functioning autism often require assistance but can have some degree of independence in their jobs and living conditions as adults. Both children and adults with level 2 autism can exhibit the following challenges.

Difficulty With Verbal Communication

Someone with moderate-functioning autism is likely to have some challenges with verbal communication. His/her conversations might be atypical and simplified and include some repetitive language or non-functional verbal actions. The individual might prefer to communicate through signs or technological devices.

Normal or Below-Normal Mental Functioning

A person with moderate autism may have some degree of mental retardation, or he or she may have a normal IQ of about 100. This person may find self-care tasks challenging.

Some Behavioral Problems

Those with level 2 or moderate-functioning autism have some fixation on certain behaviors. There is repetition of behaviors, such as walking on toes or spinning in circles. These repetitive behaviors can cause difficulties in social, school, job, and other settings.

These individuals can also be over or under-sensitive to sounds, sights, and other types of stimulation. Additionally, they might actively resist any change in their normal routine.

Social Dysfunctions

An adult or child with a moderate autism diagnosis has some degree of difficulty socializing. He or she is generally aware others are in the room but might appear aloof to other people. The individual might avoid trying to interact with others, and they may find it challenging to initiate an interaction with this person.

Level 1 or High-Functioning Autism

Girl using sensory station

Children and adults with level 1 or high-functioning autism have the mildest degree of the disorder. People previously diagnosed as Asperger's Syndrome fall in this category. Many high-functioning autistic individuals live and work independently. Those affected have the following characteristics.

Normal Verbal Skills but Difficult Communication

High-functioning autistic people have normal verbal skills but find it difficult to have normal back-and-forth conversations with others. Their tone of voice can also appear robotic or odd.

Individuals might also struggle with functional use of language. For example, he or she might know several synonyms for "beverage" but find it challenging to ask for a drink.

Normal or Above-Normal Intelligence

People with mild autistic spectrum disorders have normal intelligence and in many cases, they score well above normal on IQ tests. Despite this, they might struggle with some tasks, especially those that require them to make sudden decisions or change regular routines. It is important to note that many people with autism are considered gifted and can excel in various areas of study.

Fewer Restricted, Repetitive Behaviors

An individual with high-functioning autism engages less in restricted and repetitive behaviors than those with the higher levels of autism. He or she is less likely to disrupt others with these behaviors.

A child or adult might develop a passionate interest in a single topic. He/she can sometimes struggle with going from one task to another, which might affect schoolwork or job performance.

Atypical Social Interactions

Someone with a mild functional level of autism can struggle with the finer points of social interactions. He or she might have difficulty connecting with other children or adult peers, including making eye contact or interpreting body language and tone of voice. This person may have difficulties understanding the perspective of others.

Improvement in Functioning Levels

Autistic boy building with blocks

It's important to remember that the functioning level of an individual on the autism spectrum can change dramatically with the right therapies and treatments. The journal Pediatrics published a study reporting that one early intervention model improved children's IQs by an average of 17.6 points.

Additionally, early intervention, especially before the age of three years, can improve adaptive behaviors, social functioning, language usage, and behavioral issues. This can result in an overall improvement in the individual's ability to function at a higher level.

Variations in the Level of Impairments

Every person with autism is different, and there can variations in the level of each functional impairment in the same person. In addition, among individuals diagnosed with the same level of autism, some dysfunctions might be more prominent in some people than in others. The functioning level assigned to a child or adult also serves as a guide for what treatments, interventions, and support he or she needs to achieve the best functional outcome.

Different Levels of Autism