Levels of Autism: Common Symptoms per Level

Reviewed by:
Hannah Andreasen

April 22, 2022

The different levels of autism categorize the severity of social skills and behaviors of children with autism. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), autism is categorized by doctors as level 1, 2, or 3 according to the two areas of functioning — social communication and restricted, repetitive behaviors.

Level 1 — Requiring support

Level 1  indicates the least severe level of autism, also termed mild autism. Children under this category face challenges with social situations and may have some restrictive or repetitive behaviors. However, the amount of support required for day-to-day activities is minimal. 

These individuals are able to communicate their wants and needs verbally and also have the ability to maintain some relationships. They may feel uncomfortable with sudden changes or unexpected events that influence their lifestyle and prefer to stick to their established routines.

Level 2 — Requiring substantial support

Level 2 represents an intermediate level of severity in autism symptoms that often requires further outside support than those diagnosed with level 1.

Individuals face challenges in social situations that are more noticeable to the people around them.  Individuals diagnosed with level 2 may not be able to communicate their wants and needs verbally. If they have the ability to speak, they may only be able to communicate in short sentences or single words.  Conversations may also be difficult to initiate and maintain. As a result, these individuals may require extensive support in order to participate in social activities.

Children who are unable to verbally communicate may not acknowledge anyone talking to them or may not make eye contact with anyone talking to them. These children may only express their thoughts and feelings through their tone of voice or through facial expressions. Additionally, they can become uncomfortable or upset when their daily routines or habits get interrupted.

Level 3 — Requiring very substantial support

Level 3 is the most severe form of autism spectrum disorder. Those falling within this category have significant challenges with social communication and social skills. They may experience restrictive or repetitive behaviors more frequently which can impact their ability to function independently and complete everyday activities.  

Most individuals with level 3 autism are not able to communicate verbally, although some may use a few words for communication. These individuals may also display more severe aggression or self-injurious behavior. Level 3 individuals may become over or under-sensitive to particular stimulations from sense, smell, and touch. These individuals may exhibit behavioral characteristics such as rocking, echolalia, spinning things, or other behaviors and often struggle with unexpected events.

Symptoms of autism

Individuals with autism can show symptoms in many situations.

Symptoms of autism in social situations

  • Difficulty in initiating or maintaining a conversation
  • Difficulty in providing an appropriate response to others
  • Difficulty in expressing or discussing their interests in detail
  • Difficulty in maintaining eye contact or benign oriented towards the person while talking
  • Difficulty in understanding another’s perspective
  • Difficulty in using facial expressions that match the ongoing context of communication

Symptoms of autism in everyday life

  • Doing repetitive actions while conversing such as saying the same thing over and over again or rocking from side to side
  • Showing a high intensity of interest in a specific topic
  • Isolating or distancing themselves from others
  • Developing high skills and efficiency in certain areas, such as solving mathematical equations or arts and crafts
  • Difficulty coping with changes to their daily routine or usual environment
  • Being preoccupied with objects or other non-living things such as furniture or vehicles
  • Showing higher or lower sensitivity to simulations of sounds, smells, and touch
  • Having difficulty falling asleep

Current terms

High Functioning Autism

High functioning autism is a term used to describe what was once Asperger’s syndrome. These individuals exhibit mild symptoms and the need for support is minimal.

Broad Autism Phenotype

Broad Autism Phenotype is a term used to describe the autistic traits present within an individual without any diagnosis. These individuals typically have a mild level of symptoms that are not clinically significant and may be seen in relatives of people with autism.

Rett Syndrome

Rett Syndrome is a rare brain disorder that primarily affects girls and causes a progressive loss of motor skills and speech. Rett Syndrome may share many of the  symptoms of autism such as:

  • Difficulty speaking
  • Difficulty learning
  • Difficulty communicating
  • Difficulty coordinating with others
  • Spitting
  • Drooling
  • Rapid eye movements such as staring or blinking
  • Sleep disturbances
  • Cold extremities
  • Irritability
  • Breathing abnormalities
  • Seizures
  • Slowed growth

Other terms

Autistic disorder

Autistic disorder was previously used to describe those with severe autism symptoms including communication impairments, repetitive behaviors, and social challenges.

Asperger’s Syndrome

Asperger’s Syndrome was characterized by milder symptoms in comparison to autistic disorders that could impact an individual’s communication or social skills.

Pervasive Development Disorder (PDD)

PDD was a group of disorders characterized by delays in the development of social and communication skills in children under three.

Childhood Disintegrative Disorder

Children with this disorder would have problems maintaining the skills they’ve already acquired, such as their language skills, way of communication, social skills, self-care skills, and motor skills such as bowel and bladder control.

Bottom line

Those with autism need varying levels of support and therapy based on the level of diagnosis they receive.  With the right amount of support, various symptoms associated with autism such as irritability, aggression, obsessive behavior, hyperactivity, impulsivity, attention deficits, mood changes, and anxiety problems can be mitigated with early intervention with ABA therapy.

Songbird Therapy is a technology-enabled provider setting a higher standard for children’s autism care. With a deeply passionate team and innovative technology, we’re building a world where every child can access world-class care at home, uniquely tailored to them.