Three levels of autism exist to clarify the amount of support an autistic person might want or need.
Autism spectrum disorder (ASD) is a neurodevelopmental difference that can appear in many forms.
The Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR) outlines diagnostic criteria based on functioning in two domains:
- social communication
- restricted interests/repetitive behaviors
These criteria state that autistic people sometimes benefit from support, but there’s a wide range of differences in support needs.
Some autistic people are fluent conversationalists and might want only occasional help interpreting social cues or unpacking issues in therapy. Others get stuck and frustrated by social or functional roadblocks if they haven’t had regular coaching in relevant skill areas.
And some are nonspeaking, highly sensitive to sensory input, and communicate with emotional and behavioral outbursts when their needs aren’t recognized or met. They may use augmentative and alternative communication (AAC) tools like picture symbols or electronic devices to express their thoughts and may benefit from support in multiple areas.
When diagnosing the condition, doctors assign levels of autism to help the person get the amount of support that’s right for them.
A person can also have different levels across the two domains — for example, someone might have level 1 autism for social communication and level 2 for restricted/repetitive behaviors. Each of those criteria has its own degree of support.
A person with level 1 autism requires the least amount of support.
Level 1 social communication characteristics may include:
- trouble understanding or complying with social conventions
- the appearance of disinterest in social interactions
- some emotional or sensory dysregulation
Level 1 restricted interests and repetitive behavior traits can be:
- a need for additional personal organization strategies
- behavioral rigidity and inflexibility
- stress during transitions
- attention span differences
- perseveration (focusing on something longer than is helpful)
An autistic person at level 1 in social communication might want therapy or coaching to enable them to navigate social nuances. Therapy for level 1 restricted and repetitive behaviors can help an autistic person learn self-regulation strategies.
At school, they can benefit from accommodations like extra time for tests and intermittent support from an education assistant (EA).
An autistic person who meets the level 2 criteria in either category has similar characteristics as those in level 1 but to a greater extent.
Social communication traits at level 2 may include:
- using fewer words or noticeably different speech
- missing nonverbal communication cues like facial expressions
- exhibiting atypical social behavior, like not responding or walking away during a conversation
Restricted interests and repetitive behavior traits at level 2 might resemble:
- a high interest in specific topics
- noticeable distress when dealing with change or disruption
An autistic person at level 2 might need school accommodations like scribing or reading support, as well as an EA nearby to help with social interactions during recess and lunch breaks.
They may also have schoolwork adapted to their level and be part of a social skills group. While in high school they might participate in an off-campus job training program.
Outside school, an autistic person at level 2 might benefit from activities such as:
- speech therapy
- occupational therapy
- social skills coaching
- applied behavior analysis (ABA) therapy
An autistic person assessed as level 3 in either social communication or restricted/repetitive behaviors will need the most support and seem noticeably different at a young age.
Level 3 social communication means the person may:
- be nonspeaking or have echolalia (repeating words or phrases they hear)
- prefer solitary activities
- interact with others only to meet an immediate need
- seem unable to share imaginative play with peers
- demonstrate a limited interest in friendships
If they are at level 3 for restricted/repetitive behaviors, they might:
- engage in repetitive physical behaviors like rocking, blinking, or spinning in circles
- express extreme distress when asked to switch tasks or focus
Support for level 3 autism includes the same therapies as level 2, but at a more comprehensive level and with greater scheduling frequency. People with this level of autism might use AAC, like a speech-generating device or Picture Exchange Communication System (PECS).
Education accommodations include one-on-one time with an EA, a separate education setting like a resource room, and modified level-specific activities. In high school, they might be in a specialized program learning functional literacy and numeracy, as well as life skills.
Before the DSM-5 was published, autism was one of several diagnoses listed under the category of pervasive developmental disorders (PDD). This has since changed.
In the DSM-5 and DSM-5-TR, four of the previous PDD diagnoses are now included in the category of autism spectrum disorder:
- Asperger’s syndrome
- pervasive developmental disorder, not otherwise specified (PDD-NOS)
- autistic disorder
- childhood disintegrative disorder (CDD)
A fifth diagnosis formerly in the PDD category is Rett syndrome, which is not considered a type of autism.
You may have heard the term Asperger’s syndrome (AS) or “Aspie” in relation to autism.
People diagnosed with AS have autistic traits, plus two defining characteristics:
- typical language development
- average to above-average intelligence
The DSM-5 and DSM-5-TR no longer use the term Asperger’s syndrome. It’s an outdated diagnosis from the DSM-4. You might still hear people refer to themselves or the autistic people in their lives as Aspies or having AS, if they were identified before the arrival of the DSM-5 in 2013.
Pervasive developmental disorder, not otherwise specified (PDD-NOS) is another outdated DSM-IV diagnosis that has since been included as part of ASD in the DSM-5.
People diagnosed with PDD-NOS have significant impairments in communication and noticeable repetitive behaviors and restricted interests. They may also experience a delay in language development or live with an intellectual disability.
However, symptoms aren’t severe enough or don’t appear early enough in life, to meet the criteria for what was previously known as autistic disorder.
Also from the DSM-4, autistic disorder is the term previously used to describe autism resulting in comprehensive support needs. People diagnosed with autistic disorder have similar symptoms as those with PDD-NOS but these symptoms are more pronounced.
Childhood disintegrative disorder
According to a
Although more research is needed, the study found evidence of neurobiological differences between people with CDD and other forms of autism.
Rett syndrome results in some autistic-like traits and was previously included in the PDD category. However, researchers have since discovered that Rett syndrome results from a genetic mutation, so they no longer considered it a type of autism.
Autism is categorized into different levels based on the amount of support an autistic person might need.
The DSM-5 and DSM-5-TR include three levels of support needs for autism spectrum disorder. The previous DSM-4 categorized autism as separate diagnoses of Asperger’s syndrome, PDD-NOS, autistic disorder, and CDD.