What Is Severe Autism?

Reviewed by:
Hannah Andreasen

April 2, 2022

Understanding the symptoms of severe autism 

Children on the severe autism spectrum typically require continuous assistance and care. This form of autism is considered a severity level three. They face more challenges and disabilities than children with level one or two autism symptoms. Some autism symptoms remain common at all levels including:

Speech and social symptoms

Children on the severe autism spectrum usually face significant challenges with communication and social skills. They are also the most likely to remain non-verbal or unable to communicate effectively and may therefore require augmentative and alternative means of communication.

Sensory dysfunction

Many children with level 3 autism often have sensory dysfunction. That implies they're either hyper- or hypo- sensitive to:

  • Sound
  • Light
  • Touch
  • Taste
  • Smell

Cognitive challenges

Some children with autism may have increased IQs (Intelligent Quotient). However, generally speaking, children with severe autism have low to excessively low IQs. Since these children are often non-verbal, their IQs are measured using non-verbal testing tools such as spelling boards, sign language, or other such methods.

Repetitive behaviors

Many children with autism usually have self-stimulatory and repetitive behaviors. Some children might often flick their fingers, flap their hands, or rock themselves. Usually, they can manage these behaviors on their own, however, children with severe autism are likely to have extreme and uncontrollable behaviors.

Physical symptoms

Children with autism of all levels often have physical symptoms that include:

  • Sleeplessness
  • Epilepsy
  • Gastrointestinal challenges

For children with severe autism, however, this can be a source of larger problems. Due to their communication challenges, such issues can go undiagnosed or undetected. The undiagnosed physical condition can often lead to physical discomfort, which may cause or worsen behavioral concerns.

What are the challenges that children face in severe autism?

The excessive behaviors of children with severe autism may result from sensory overload, frustration, or physical pain. In addition, some children with severe autism express themselves through threatening behaviors.


While self-injury can happen among children with milder symptoms of autism, behaviors such as head-banging, self-biting, and self-hitting, are far more common symptoms among children with severe autism.

Aggressive behaviors

These behaviors may include biting, hitting, kicking, scratching hair-pulling, and other similar behaviors.

Understanding the difference between moderate and severe autism

Behavioral pattern 

Intellectual and communication challenges cause children with moderate autism to show many distinctive behaviors. They may flutter their hands, hit, rock, grind their teeth, scratch, or get obsessed with any specific object when they get upset, bored, joyful, frustrated, or unable to communicate their feelings or needs. 

While these and other behaviors can be a form of communication for children with autism, they can sometimes be dangerous for the child and parents. Some of these behaviors will persist throughout their lives however, ABA therapy, communication techniques, and other tools can assist children in learning to communicate their needs safely, effectively, and independently. 

The behaviors of children with severe autism are comparable to those displayed by children with moderate autism, however,  to a greater extent. Typically more challenging to manage, these behaviors consist of a variety of stimulating, self-soothing, or communicative behaviors like flapping, rocking, hopping, aggression toward other people, and self-injury. 

Even with the most impactful autism therapies to help children with severe autism symptoms cope and communicate, they might continue to show these behavioral symptoms to some extent throughout their lives and require constant support.

Language and communication

Language and communication capabilities generally remain restricted in children with moderate autism. They may develop language skills later than ‘normal’ and speak less than their typically developing peers. In some circumstances, children on the moderate-level autism spectrum (level 2) are non-verbal or cannot pronounce words correctly. 

Depending on intellectual capabilities, children on a moderate autism level might learn to interact through augmentative and alternative communication, such as PECS or SGD, Picture Exchange Communication Systems and Speech Generating devices, respectively. On the contrary, children on the severe autism spectrum generally hold limited language and communication abilities. If they can communicate, they may repeat phrases and words they hear from others or speak only a few words that might not match the context.  They may also learn to use augmentative and alternative communication such as PECS and SGDs.

Children with severe autism may communicate through groans, sounds, and other gestural body patterns. Parents or caregivers can use interaction, observation, ABA and speech therapy to learn to understand their child's needs and find new ways to improve language and communication with them. 

The limitations of children on the severe autism spectrum (level 3) typically significantly limit social interactions. Other children may be upset by children with autism who have repetitive behaviors and may communicate their distress, thoughts, and feelings through maladaptive behaviors.

Sensory concerns

When confronted with overwhelming sensory input, the children might experience a breakdown and display maladaptive behaviors. Parents must understand their child’s sensory triggers and take measures to create a non-threatening surrounding. 

The bottom line

Educating yourself on the signs, symptoms, and challenges your child may face is one of the best things you can do to prepare yourself as a parent or caregiver. Luckily, you don’t have to do it alone — there are whole hosts of medical professionals ready to help you navigate behavioral health challenges. 

At  Songbird, we believe every child deserves world class care. Contact us today to learn how our passionate therapists can develop a holistic care plan uniquely tailored to support your child in their growth and development.