Signs such as reduced social and motor skills can be the first indication that a child is autistic. Signs of regression can also occur later, such as during adolescence.

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Autism spectrum disorder (ASD) is a neurodevelopmental difference. It can affect the way a person thinks, behaves, and communicates.

ASD exists on a broad spectrum.

Some autistic people are comfortable with their differences and want little support, if any. Others benefit from varying support that helps them interact with a mostly allistic (non-autistic) world.

Sometimes, the gap widens between autistic and allistic thinking, behaviors, and communication. This can occur in a phenomenon known as regressive autism.

Regression is a return to a former state or a state that’s less developed.

Regressive autism occurs when an autistic person’s differences become more pronounced.

  • Early regression: At about 18 to 24 months of age, signs of autism emerge in a previously unidentified child.
  • Late regression: During adolescence, regression can occur in a previously identified autistic person after a childhood of stability.
  • Autistic burnout: This is the onset of debilitating symptoms like exhaustion and withdrawal, which accompanies a general reduction in functioning, caused by having to mask in or adapt to the allistic world.

Autistic regression usually occurs in language and social areas. This doesn’t mean that an autistic person loses their ability to think or feel. Instead, the way they convey their experience changes.

Social regression by itself is rare. Usually, the social quieting associated with regression is of the communicative behaviors that accompany language.

As the autistic person’s verbalizations decrease, so does their nonspeaking communication.

Researchers also use the term “mixed regression” to describe other areas, such as motor skills, but most regression seems to involve decreased verbalization.

An estimated one-third of preschool-aged autistic children experience a reduction in some skills, including:

  • speech
  • nonverbal communication
  • play and social skills

Other early regression signs include loss of:

  • eye contact
  • social interests
  • imitative games
  • motor skills
  • self-feeding
  • toileting

A 2019 study of autistic people experiencing late regression noted the following regression signs:

  • an increase in compulsive rituals
  • an increase in obsessive slowing (completing tasks extremely slowly)
  • aggression
  • motor abnormalities
  • mood disturbances

Adults living through autistic burnout may experience:

  • withdrawal
  • exhaustion
  • executive function problems
  • reduced general functioning
  • increases in autistic traits

Researchers have identified a few possible contributing factors to regressive autism. These factors may influence how an autistic person’s brain functions.

Gastrointestinal inflammation

Older research from 2003 found a connection between regressive autism and inflammatory intestinal issues.

In the study, researchers found that the colons, ileum, and duodenums of children with regressive autism were more like those of the study’s inflamed controls than the noninflamed participants.

The study data suggested that children with regressive autism live with intestinal mucosal immune system changes that differ from other inflammatory bowel diseases.

A person’s gastrointestinal health can impact their cognition, mood, and mental health, according to research from 2018. This describes the two-way influence between the gut and brain.

Mitochondrial differences

There’s also research indicating that some autistic children may have mitochondrial differences.

Mitochondria generates the cellular energy that drives many vital bodily functions, including brain activity.

Researchers speculate that abnormalities in the mitochondrial respiratory chain can lead to the onset of autism symptoms in some people.

The mitochondrial respiratory chain is an enzyme reaction system that gives cells their energy.


Autoimmunity may underpin regressive autism, according to research from 2021 that notes a link between infection, immune-related issues, and autism. Infection may trigger autism signs in previously unidentified children or regression in autistic people.

Researchers describe a syndrome called autoimmune encephalitis (AE), where the immune system mistakenly attacks healthy brain cells and causes neuroinflammation. AE can lead to autism or autistic-like traits in some people.


An estimated 70% of autistic people live with the stress of a co-occurring mental health issue like depression or anxiety.

Researchers think that core autistic traits can make a person more vulnerable to mental health stresses.

For example, an autistic person’s social anxiety might stem from autistic vs allistic differences in socialization styles and priorities.

Things like unplanned schedule changes, sensory overload, and social pressure to avoid self-soothing behavior like stimming can also be stressful.

Adverse childhood experiences (ACEs), like school difficulties and bullying, can even lead to post-traumatic stress disorder (PTSD) for autistic people.

Masking, or trying to fit into an allistic society, can lead to autistic burnout for adults.

Stress, autistic burnout, PTSD, and associated mental health issues can lead to regressive autism.

There’s a range of support options available, depending on the needs of the individual.

Examples include:

  • speech therapy
  • Augmentative and Alternative Communication (AAC)
  • visual supports and schedules
  • behavioral interventions
  • joint attention interventions
  • family therapy
  • individual therapy
  • physical therapy
  • literacy support
  • occupational therapy
  • play therapy
  • communication training
  • role play
  • social story-based intervention
  • peer-mediated intervention

Although early regressive autism may not be fully reversible, often, the sooner the child receives support, the easier it is for them to learn functional skills.

Regressive autism describes an autistic person’s reduction in skills like socialization and verbalization.

Early regression occurs at around 2 years of age and can lead to a child being identified as autistic. Late regression occurs during adolescence. Autistic burnout can lead to regression in adulthood.

Support can provide autistic people with skills and coping strategies to make living in an allistic world easier.