By Aaron Kandola, Reviewed by Karen Gill, MD

Autism is a spectrum disorder that causes social and behavioral problems. There are three different levels of autism, which range from mild to severe.

According to the Centers for Disease Control and Prevention (CDC), about one in 59 children have autism. Signs of the condition are usually present at a young age, but occasionally people do not receive a diagnosis until adulthood.

According to the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5), doctors categorize autism by assigning level 1, 2, or 3 to two of the domains of symptoms.

One severity score is for impairment in social function, while a second severity score is for restrictive, repetitive behaviors. The levels the doctor assigns depend on the severity of the symptoms.

A correct autism diagnosis that includes the levels of severity can help doctors and other specialists work with the individual to provide the right treatment and support. In this article, learn more about the levels of autism.

Levels of autism

The DSM-5 states that there are three levels of autism:

Level 1: Requiring support

Man with autism looking anxious, concerned, or awkward A person with level 1 autism may have difficulties in social situations.

Level 1 is the least severe autism diagnosis. People in this category have social difficulties that require some support.

They can find it difficult to initiate conversations with others and may respond inappropriately or lose interest quickly. As a result, it can be challenging for them to make friends, especially without the right support.

People with level 1 autism may also show inflexible behaviors. It can be difficult for them to cope with changing situations or contexts, such as new environments. They may need help with organization and planning.

Level 2: Requiring substantial support

People in this category need more support than those with a level 1 diagnosis. They have more severe social deficits that make holding a conversation very challenging.

Even with support, they may struggle to communicate coherently and are more likely to respond inappropriately to others. They may speak in short sentences or only discuss very specific topics.

These individuals may also have issues with nonverbal communication and might display behaviors such as facing away from the person with whom they are communicating.

People with a level 2 diagnosis may also have inflexible behaviors that can interfere with daily functioning. They typically do not cope very well with changes, which can cause them significant distress.

Level 3: Requiring very substantial support

Level 3 is the most severe autism diagnosis. People with a level 3 diagnosis have significant impairments in their verbal and nonverbal communication.

They will often avoid interactions with others, but they may interact in a limited way if they must respond to others or communicate a need.

Their behaviors are highly inflexible and repetitive. They may react strongly to changes and become highly distressed in a situation that requires them to alter their focus or task.


Symptoms of autism

Senior mature adults doing painting and art therapy outdoors


Potential symptoms of autism include obsessive interests and developing high levels of skill in areas such as art.

The symptoms of autism are usually both social and behavioral.

Social symptoms include:

  • difficulty initiating or maintaining a conversation
  • responding inappropriately to others
  • discussing their interests in great detail
  • avoiding eye contact
  • facial expressions that do not match the context of communication
  • difficulty understanding perspectives other than their own

Behavioral symptoms include:

  • repetitive behaviors, such as rocking from side to side or saying the same thing over and over again
  • distancing themselves from others
  • having obsessive interests in specific topics
  • developing a high level of skill in certain areas, such as mathematics or art
  • an inability to cope with changes to their routine or environment
  • becoming preoccupied with specific parts of an object, such as the wheels on a car
  • being more or less sensitive to sensory stimulation, such as loud noises
  • having problems sleeping


Autism can be challenging to diagnose because it is a spectrum disorder.

The symptoms of spectrum disorders can range from mild to severe, and the types of symptom will differ among individuals. Some people have very mild symptoms that are difficult to detect.

Early diagnosis is important for treatment and can provide a better quality of life for people with autism.

In children, the most obvious signs of autism are usually detectable by the time they are 2 to 3 years old. However, it is possible to start showing signs at an older or younger age.

Diagnosing a child with autism involves two stages:

  1. Developmental checkups: All children should receive routine developmental screening at each checkup as they age. A doctor will typically assess a child for signs of autism at around 18 or 24 months. They will also discuss the child's behavior, development, and family medical history with a parent or caregiver.
  2. Additional evaluation: if a doctor suspects that a child has autism, they will arrange for additional checks by a team of healthcare professionals, such as child psychiatrists and speech and language pathologists. These specialists will primarily assess cognitive and language skills. Further tests may also be necessary to rule out other conditions.

In older children, it is possible that teachers, caregivers, parents, or anyone else who interacts with the child may pick up on signs of autism, which should prompt an evaluation by their doctor.

Making a diagnosis can be more challenging in adults as the symptoms of autism can overlap with those of other mental health issues. It may sometimes be up to the person to seek professional help.


Child with autism in therapy speaking with adult or parent, avoiding eye contact and looking anxious




Children with autism may benefit from behavioral therapy.

Autism is a lifelong condition, but treatment and therapy can help a person manage it.

Although there is no medication specifically for autism, doctors often diagnose other conditions in people with autism. A range of medications can help reduce the following symptoms:

  • irritability
  • aggression
  • obsessive behavior
  • hyperactivity
  • impulsivity
  • attention deficits
  • mood changes
  • anxiety problems

Educational and behavioral therapies can also help people with autism, especially younger children. These interventions can focus on the particular areas that the child is finding challenging.

For example, a specialized therapist may aim to improve social and language skills in a classroom, which can help a child with autism maintain conversations with others and develop the skills necessary to live independently.

Some forms of therapy will involve family members or others who have regular contact with the child. Participating in therapy can help family members and caregivers understand the condition and learn constructive ways to provide support.


The outlook for people with autism depends on a range of factors, such as the severity of the condition and how early they receive a diagnosis.

People with a level 1 diagnosis may be able to live a relatively independent life with minimal support. Those with a level 3 diagnosis will be more dependent on others, but medication and therapy can help manage some of the symptoms.

Early diagnosis and individualized treatment can help a child or adult with autism develop skills that allow them to live as independently as possible.