Regressive autism is a very rare condition. A child appears to show normal social, emotional, and language development, and then loses their speech and social skills for no discernible reason.

This usually develops between 15 and 30 months of age. It can take place very suddenly or gradually. The child usually struggles to regain the skills that they have lost. 

Regressive autism is also known as acquired autistic syndrome, autism with regression, and autistic regression.

The Debate About Regression

In “Rethinking Regression in Autism,” Spectrum explains what the standard, and somewhat outdated and misunderstood, picture of regressive autism looks like. A 2-year-old child who had been developing very neurotypically “suddenly withdraws,” ignoring the sound of his own name, speaking less to the point of not speaking at all, ignoring play with other children in favor of playing almost exclusively with inanimate objects, and losing interest in hobbies while obsessively focusing on just a few activities. Other skills that were once normally coming along are lost, and the child starts to display repetitive and odd behavior. 

For decades, regressive autism was thought to be a subtype of autism. More recent research has suggested that as many as 40% of the diagnoses of autism fit the regressive model. Much of the change is because the clinical understanding of both autism spectrum disorder, and regression itself, is evolving. 

How common is regressive autism? Estimates of the rate of regression — as many as one in five cases, according to a study published in the Journal of Developmental and Behavioral Pediatrics — have risen as studies have grown to include more people with unique presentations of autism spectrum disorder. This growing body of research has challenged what used to be the standard view of regressive autism. 

Regression & a Range of Onset Patterns 

It used to be thought that there was a clean distinction between regressive autism and non-regressive autism. Today, more and more doctors argue that such classifications are meaningless.

While most children with autism lose some skills, there is considerable variation in the types of skills lost, at what ages, and to what degrees. Doctors note that the more they examine a patient’s history and home environment, the more they see signs of classic autism and not neurotypical development that was suddenly lost.

Other research concurs. A 2016 study published in the Autism journal found “a range of onset patterns,” extending from early developmental delays with no loss of skills to no such delays before a clear loss. 

With this in mind, some clinicians say that what is commonly thought of as regressive autism should instead be presented as any number of different kinds of onsets of autism spectrum disorder. Instead of a black-and-white distinction between “standard” autism and regressive autism, there is actually “a complex kaleidoscope of possibilities” regarding the loss of social, emotional, and communication skills.

A Boy Who ‘Disappeared’

The question of the frequency of regressive autism was debated across a series of articles in 2014. First, an excerpt from a book in the New York Times Magazine told the story of Owen, who “disappeared” just before he turned 3 years old, becoming silent, refusing to make eye contact, and losing motor skills. Doctors diagnosed Owen with regressive autism, placing him in a different category than the children “born with it.”

Owen retained a fascination with Disney movies, eventually prompting his parents to use characters and concepts from those stories to harness his desire to communicate. After a number of setbacks, Owen’s family and a psychologist used Disney movies to help Owen develop communication and social skills.

The project was wildly, if painstakingly, successful. By age 20, Owen was leading a full and happy life. 

The Rarity of Regressive Autism

Encouraging as the story was, many parents reading it wondered if their own children would go on to develop regressive autism. This led Jennifer Richler, writing in Slate magazine, to say that regressive autism does not exist as it is broadly understood. At later ages, the phenomenon of children losing their skills becomes increasingly unlikely.

Herself an autism researcher, Richler argues that Owen’s experience is “very rare.” Most of the autism-positive children who experience regression “do not have typical development to begin with,” usually having some delays in the development of their skills and even experiencing loss in some of the skills they attained.

Losses tend to occur earlier than the age of 3. The average age of regression is 21 months. 

Richland also wrote of studies that have found that most of the children with autism spectrum disorder lose some skills and gain others within the first two years of their lives. One example comes from the Development and Psychopathology journal, which found that only 6% of children lose all their skills (like Owen). Those who did had limited skills to begin with. The rest tended to retain a majority of their skills, even as some critical ones were lost. 

Richland cautions that the stories of children regressing “are real and haunting,” but reassures readers and anxious parents that this kind of regressive autism is rare, and that Owen’s case (and the work of his parents and a therapeutic team) is an uncommon example of one way that late-onset autism can appear. 

Missed Signs

Commenting on Richland’s article in Forbes magazine, Emily Willingham clarifies that regression in autism is less about when the symptoms appear and skills are lost, and more a case of “a critical threshold” of missed signs and accumulated deficits that finally become apparent and unmistakable.

Willingham quotes an article published in the Journal of the American Academy of Child and Adolescent Psychiatry where researchers argued that parental reports of classifying the onset of autism (based on standard methods like the Ages and Stages Questionnaire, the Parents’ Evaluation of Developmental Status, and Child Development Inventories) are flawed, outdated, and in need of improvement. 

The authors of the study wrote that autism tends to develop along a spectrum of three trajectories: early-onset autism showing low social-communication skills early in life; regression showing high levels of social-communication skills early on, which declined over a period of two years; and a plateau category showing typical levels of communication in the first year, but stagnation and a failure to make expected progress at the expected rate. 

Therefore, the loss of social interest takes place at varying ages. There is no point after which the autism “kicks in.”

When autism is looked at on this spectrum, noticing the loss of communication skills becomes easier when it happens in children for whom the loss appears to take place when they’re older and is thus quite sudden. When it happens in very young children, the decline appears to be more subtle, which is why the signs are missed until they become drastically obvious.

Parent Reports

Another study from the Journal of the American Academy of Child and Adolescent Psychiatry confirmed that parents are good at detecting developmental delays in their children when those delays present early on. However, when children experience a “sharp decline” between 6 and 18 months after a period of typical development, this goes unnoticed by the parents. 

On other hand — and crucially — parents who had more time to get used to the idea of having a neurotypical child for 12 months or more tended to report that the eventual decline was more pronounced, giving rise to the belief that their child experienced a “regressive” form of autism. 

Can Regressive Autism Be Reversed?

Can regressive autism be treated or even reversed? The BMC Medicine journal suggests that corticosteroid therapy might have some effectiveness in arresting the rate of regression in certain children.

The idea comes from the use of such medication in Landau-Kleffner syndrome (LKS), a rare childhood disorder where children lose language comprehension and verbal expression. LKS is not an autism spectrum disorder. It is more associated with seizures because it causes “severely abnormal electroencephalographic” activity when patients are asleep. 

Other research, like that published in the Neurotherapeutics journal, has looked at a possible connection between the autoimmune system and the pathophysiology of autism, which “raises the possibility that steroids might be a useful therapy for regression in autism spectrum disorder.”

A study in the BMC Neurology journal looked at 20 people with regressive autism symptoms who had received steroid treatments and found that they had improved in clinical functions. The BMC Medicine researchers suggested that, in light of there not being an established treatment for autism with regression, especially pertaining to the loss of language skills, corticosteroid therapy might be a cautious starting point for further testing.

Regressive autism remains a debated topic in research of the disorder. The current consensus suggests that regression is a standard feature of autism, but one that takes place at different ages for different people. As a result, it can be hard to anticipate or notice.