What Are the Three Levels of Autism?

Levels of autism spectrum disorder (ASD) are defined in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5). The 5th edition criteria for autism diagnosis provides three clear levels based on the patient’s requirements for support. These levels of autism allow specialists to make more refined diagnoses, allowing for more effective treatment plans and helping caretakers better understand individuals’ symptoms and needs.

ASD Level 1: Requiring Support

Level 1 is the mildest, or “highest functioning” form of autism, which includes those who would have previously been diagnosed with Asperger’s syndrome. Individuals with ASD level 1 may have difficulty understanding social cues and may struggle to form and maintain personal relationships. A child with level 1 autism may understand and speak in complete sentences, but have difficulty engaging in back-and-forth conversation.

Children with ASD level 1 experience some inflexibility of behavior, like difficulty switching between tasks, staying organized, and planning.

ASD Level 2: Requiring Substantial Support

Social communication and repetitive behaviors present themselves more obviously in children with ASD level 2 than in children with level 1 autism. Children on this level have challenges in verbal and nonverbal communication, as well as reduced or abnormal responses to social cues.

Inflexibility of behavior is also more pronounced than in ASD level 1. Repetitive behaviors appear more frequently and may be obvious to casual observes. Likewise, children with level 2 autism may have difficulty coping with changes in routine, which can cause challenging behavior.

ASD Level 3: Requiring Very Substantial Support

ASD level 3 is characterized by severe challenges in social communication as well as extremely inflexible behavior. Children with level 3 autism will be nonverbal or have the use of only a few words of intelligible speech. Initiation of social interaction is very limited, as well as response to others. An individual at this level may interact with others abnormally, and only to meet immediate needs.

Individuals with level 3 autism exhibit marked inflexibility of behavior, with extreme difficulty coping with changes to routine. At this level, restrictive or repetitive behaviors interfere with the individual’s ability to function. Changing focus from one activity to another may come at great difficulty and cause significant distress.

Outdated Autism Diagnoses

The previous diagnostic manual (DSM-IV) defined five subcategories of autism, including Asperger’s syndrome (mild, or high-functioning autism) to autistic disorder (severe autism), which are now considered outdated diagnoses. It also included Rett syndrome and childhood disintegrative disorder (CDD), both rare disorders which are no longer considered part of the autism spectrum.