Are There Different Types of Autism?

Are there different types of autism?

Not as separate diagnoses anymore. Since the DSM-5 in 2013, the American Psychiatric Association’s manual has one diagnosis, autism spectrum disorder, in place of the separate pervasive developmental disorders it used before, and the current DSM-5-TR no longer specifies subtypes.⁠^1,2

The World Health Organization’s ICD-11, in effect since January 1, 2022, made the same move: its single category, 6A02 autism spectrum disorder, brings ICD-10’s childhood autism and Asperger syndrome together.⁠^11,12

What remains are ways of describing differences within the one diagnosis. The DSM-5 rates the support a person needs at three levels and adds specifiers, such as with or without intellectual or language impairment, while ICD-11 sets a subcode from intellectual development and functional language.⁠^3,4,13

How many types of autism are there?

Officially, one: autism spectrum disorder.⁠^1,4 Other counts come from older systems or from research. The DSM-IV, used until 2013, had five pervasive developmental disorders; ICD-11 divides its one diagnosis into seven subcategories; and a 2025 study sorted autistic children into four research groups that are not diagnoses.⁠^4,13,14

Why were the separate types of autism removed?

Because they did not hold up in practice. The American Psychiatric Association’s DSM-5 fact sheet says researchers found the separate DSM-IV diagnoses “were not consistently applied across different clinics and treatment centers.”⁠²

A 2012 study tested this directly, with 2,102 children and teenagers at 12 university autism centers. The children’s scores on standard assessments looked alike from site to site, yet which specific diagnosis they received depended on the site, and the authors concluded the subtypes “were not reliable.”⁠⁵

A 2021 history of the diagnosis by Rosen, Lord and Volkmar lists four findings behind the change.⁠¹³

• Overlapping groups

  Symptoms varied in number and severity within each subtype and between subtypes with similar core profiles.⁠¹³

• No help predicting the future

  The subtype a child received did little to predict later outcomes.⁠¹³

• Unreliable labels

  Poor diagnostic clarity limited how reliably clinicians could assign a subtype.⁠¹³

• Services tied to labels

  Treatment eligibility and coverage were sometimes restricted by subtype.⁠¹³

The change was controversial. Some people felt it took away part of their identity and community, particularly those diagnosed with Asperger’s, and there were concerns that people would lose services; the same review notes that the evidence for real subcategories “has continued to be very weak.”⁠¹³

What does “autism spectrum” mean?

It means autism shows up in many different ways. The National Institute of Mental Health (NIMH) explains that autism is called a spectrum disorder because people with autism have a range of characteristics, needs, strengths and challenges.⁠¹⁵

CDC gives examples of how wide that range is: some autistic people have advanced conversation skills while others are nonverbal, and some need a lot of help in daily life while others work and live with little to no support.⁠¹⁶

Intellectual ability varies just as widely. WHO describes it as extending from profound impairment to superior levels, and in CDC’s 2022 surveillance of 8-year-olds, 39.6% of autistic children with test results had an intellectual disability, 24.2% scored in the borderline range and 36.1% in the average range or higher.⁠^17,18

The range is not only from mild to severe. The American Psychiatric Association describes symptoms that fall on a continuum from mild to much more severe, and WHO adds that abilities and needs vary and can change over time, so two autistic people with the same diagnosis can need very different support.⁠^2,17

Is autism the same as autism spectrum disorder?

Yes. Autism spectrum disorder, or ASD, is the medical term for a diagnosis of autism, and “autism” is the everyday word for the same thing.⁠¹⁹ “On the spectrum” is an informal way of saying a person is autistic; NIMH uses the phrase itself when it advises adults who wonder whether they are on the autism spectrum to ask for an evaluation.⁠¹⁵

What symptoms do all types of autism share?

Two core areas: lasting differences in social communication and interaction, and restricted or repetitive behaviors or interests.⁠^3,20 Under the DSM-5, a diagnosis needs difficulties in all three areas of social communication plus at least two of four kinds of restricted, repetitive behavior.⁠³

• Social communication and interaction

  Differences in back-and-forth social exchange, in nonverbal communication such as gestures and eye contact, and in making and keeping relationships; for example, using few or no gestures by 12 months.⁠^3,20

• Repetitive movements or speech

  Repeated movements, lining up toys, or repeating words or phrases over and over (echolalia).⁠^3,20

• Insistence on sameness

  Strong distress at small changes, trouble with transitions, and rigid routines.⁠³

• Intense, focused interests

  Interests that are unusually strong in intensity or focus.⁠³

• Sensory differences

  Over- or under-reaction to sounds, smells, tastes, sights or touch, or unusual interest in sensory experiences.⁠^3,20

• Present from early childhood

  Signs are present in the early developmental period, though they may not be fully clear until social demands exceed a child’s capacities.⁠³

Not every autistic child shows every sign, and some children without autism show a few of them.⁠²⁰ Doctors look at the child’s developmental history and behavior as a whole to make a diagnosis.⁠²¹

Read nextAutism: signs, diagnosis and support

What were the old types of autism in the DSM-IV?

The DSM-IV, in use from 1994 until 2013, grouped five diagnoses as pervasive developmental disorders: autistic disorder, Asperger’s disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), Rett’s disorder and childhood disintegrative disorder.⁠^1,13 The DSM-5 eliminated that category.⁠¹

What was autistic disorder, or classic autism?

Autistic disorder was the DSM’s name for the condition Leo Kanner first described in 1943, in 11 children (8 boys and 3 girls).⁠¹³ “Classic autism” and “Kanner’s autism” are informal names for it; ICD-10 listed Kanner syndrome under childhood autism, F84.0.⁠^13,22

Autism entered the DSM for the first time in the DSM-III of 1980, as “infantile autism”; the 1987 revision renamed it autistic disorder.⁠¹³ ICD-10’s childhood autism required differences that showed before age 3 in all three areas the manual named: social interaction, communication, and restricted, repetitive behavior.⁠²²

Read nextClassic autism: what the term means today

What was Asperger’s syndrome?

Asperger’s was a diagnosis for autism without a general delay in language or cognitive development.⁠²² It takes its name from Hans Asperger, whose 1944 report described boys with marked social difficulties, unusual, narrow interests and good verbal skills.⁠¹³

The DSM-IV made Asperger’s disorder a separate diagnosis in 1994.⁠¹³ In ICD-10 it was a single code, F84.5, with no subtypes beneath it, so ICD-10 recognized no types of Asperger’s.⁠²² Today a well-established Asperger’s diagnosis is given as autism spectrum disorder, and WHO maps Asperger syndrome to ICD-11 code 6A02.0: autism without a disorder of intellectual development and with mild or no impairment of functional language.⁠^3,6

Read nextWhy Asperger’s was removed from the DSM-5

What was PDD-NOS?

PDD-NOS, pervasive developmental disorder not otherwise specified, was the catch-all category for people with clear autistic differences who did not meet the criteria for another pervasive developmental disorder.⁠^2,24 It first appeared in 1987, as the DSM-III-R’s residual or subthreshold category.⁠^13,24

In the DSM-IV-TR it explicitly included atypical autism: presentations that missed autistic disorder because of a late age of onset, atypical symptoms, subthreshold symptoms, or all three.⁠²⁴ It was also common: in CDC data from 2010, PDD-NOS made up 46% of pervasive developmental disorder diagnoses, autistic disorder 43% and Asperger syndrome 11%.⁠²⁴

Whether PDD-NOS meant milder autism is not settled. A 2023 systematic review of 81 studies found it milder on average than autistic disorder, while WHO described its ICD-10 counterpart, atypical autism, as arising most often in people with profound intellectual disability.⁠^22,24

Read nextPDD-NOSAtypical autism (ICD-10 F84.1)

What was childhood disintegrative disorder?

Childhood disintegrative disorder, also called Heller’s syndrome, was a rare diagnosis for a child who developed typically and then lost skills. ICD-10 defined it as “a period of entirely normal development” followed by a definite loss of previously acquired skills in several areas over a few months.⁠²² Theodor Heller described the pattern more than 100 years ago and called it dementia infantilis.⁠²⁵

The DSM-5 retired it. The American Psychiatric Association says anyone diagnosed with one of the four DSM-IV disorders, childhood disintegrative disorder among them, should still meet the criteria for autism spectrum disorder or another, more accurate DSM-5 diagnosis.⁠² WHO’s ICD-10 to ICD-11 map sends it to 6A0Z, neurodevelopmental disorders, unspecified, and ICD-11 instead records loss of skills with a qualifier on the autism code.⁠^4,6

Read nextChildhood disintegrative disorder

Why is Rett syndrome no longer an autism diagnosis?

Because it is a distinct genetic disorder. The DSM-5-TR lists Rett syndrome as a separate diagnosis, noting that social interaction may be disrupted during its regressive phase.⁠¹ Nearly all cases are caused by a mutation in the MECP2 gene, and it most commonly affects girls, though boys are rarely affected.⁠²³

ICD-11 moved it out of the mental and neurodevelopmental chapter altogether, to code LD90.4 in its chapter on developmental anomalies, and lists it among the exclusions from autism spectrum disorder.⁠^4,6

Read nextRett syndrome

How has the autism diagnosis changed since 1943?

It has gone from Kanner’s description of 11 children to one broad diagnosis, and along the way the definition has alternated between broader and narrower views of autism.⁠¹³ The main steps, in the American (DSM) and international (ICD) manuals, are these.⁠^11,13

What did the DSM-5-TR change about autism in 2022?

One wording fix. The DSM-5 said social communication deficits had to be shown “as manifested by the following,” which could be read as one of the three or all three.⁠²⁶ Since the work group had always meant to require all three, the DSM-5-TR changed the phrase to “as manifested by all of the following.”⁠²⁶

What were the ICD-10 autism codes?

ICD-10, the World Health Organization’s classification before ICD-11, grouped autism under F84, pervasive developmental disorders: differences in social interaction and communication together with restricted, stereotyped, repetitive interests and activities.⁠²²

The United States codes diagnoses in its own version, ICD-10-CM. In the fiscal year 2027 code set, F84.0 autistic disorder includes autism spectrum disorder and Kanner’s syndrome, F84.5 is Asperger’s syndrome, and atypical autism sits under F84.9, pervasive developmental disorder, unspecified.⁠²⁷

Read nextWhat the ICD-10 code F84.1 meant

How does ICD-11 classify autism?

With one diagnosis, 6A02 autism spectrum disorder, and a subcode that records two things about the person: whether they also have a disorder of intellectual development, and how much functional language they have.⁠^4,12 Functional language means the ability to use spoken or signed language for practical purposes, such as expressing needs and wishes.⁠⁴

A disorder of intellectual development is diagnosed separately and graded mild, moderate, severe or profound.⁠⁴ A final digit records whether the person has lost skills they once had: 6A02.x0 without loss of previously acquired skills, 6A02.x1 with it.⁠⁴

ICD-11 says that loss of skills is part of the history of a small proportion of autistic people, typically in the second year of life and most often affecting language and social responsiveness, and that it is rarely seen after age 3.⁠⁴

What are the levels of autism?

The DSM-5 describes autism in three levels of current severity, rated separately for social communication and for restricted, repetitive behavior: level 1, requires support; level 2, requires substantial support; and level 3, requires very substantial support.⁠³ Each level states how much support a person needs in that area.⁠¹

1. Level 1: requires support

   The lowest of the three ratings of support need; it still means the person requires support.⁠³

2. Level 2: requires substantial support

   The middle rating. A person can be rated at a different level in each of the two areas.⁠³

3. Level 3: requires very substantial support

   The highest rating of support need in the DSM-5.⁠³

Which autism level is considered high-functioning?

None, officially. “High-functioning” is not a DSM term; level 1, “requires support,” is simply the lowest of the three ratings of support need, and it still means a person requires support.⁠^3,7 Researchers have found that IQ, which the label usually rests on, is a weak predictor of how a person manages everyday life.⁠⁷

Can autism levels change over time?

Yes. The American Speech-Language-Hearing Association (ASHA) notes that levels of support may vary by context and may fluctuate over time, and WHO says autistic people’s abilities and needs can evolve over time.⁠^1,17 The DSM-5 asks for current severity, so a level describes the person at the time of the evaluation.⁠³

How are autism levels used in practice?

Unevenly. In CDC’s autism surveillance network, fewer than half (40.4%) of children with an autism diagnosis had any severity level in their records, ranging from 4.8% to 73.2% by site, and the authors concluded that this limits the levels’ usefulness for identifying needed services.⁠²⁸

The levels were introduced with little description of how to assign them, and a review of the field notes the severity measure has shown questionable validity.⁠^13,28 ASHA advises that the severity rating should not be used to decide eligibility for any service.⁠¹

Is there a level 4 or level 5 autism?

No. The DSM-5 describes severity in three levels only.⁠³ ICD-11 has no levels at all; it uses its intellectual development and functional language subcodes instead.⁠⁴

RelatedHigh-functioning autismLow-functioning autism

What are the DSM-5 autism specifiers?

Specifiers are notes added to an autism diagnosis to describe things that often come with it. The DSM-5 lists five, alongside the severity levels.⁠³

• Intellectual impairment

  With or without accompanying intellectual impairment.⁠³

• Language impairment

  With or without accompanying language impairment.⁠³

• A known condition

  Associated with a known medical or genetic condition or environmental factor.⁠³

• Another disorder

  Associated with another neurodevelopmental, mental or behavioral disorder, such as ADHD.⁠^3,4

• Catatonia

  With catatonia, a cluster of changes in movement, speech and behavior.⁠^3,29

Specifiers describe conditions that often come with autism, such as intellectual or language impairment, separately from autism itself.⁠¹³ Intellectual disability and autism frequently occur together, and the DSM-5 diagnoses both when social communication is below what would be expected for the person’s general developmental level.⁠³

What does autism with catatonia mean?

It means catatonia occurs alongside autism. Catatonia is a complex syndrome of abnormal motor, vocal and behavioral symptoms, and some of its features, such as mannerisms and echolalia, overlap with autism.⁠²⁹ A 2021 meta-analysis of 7 studies (969 people, average age about 21) estimated that 10.4% of autistic people have catatonia.⁠²⁹

If an autistic child or teen starts moving or speaking much less, freezes in postures, or stops responding in a way that is new for them, talk to their doctor; ICD-11 notes that catatonic states have been described in autism.⁠^4,29

What do high-functioning, low-functioning and profound autism mean?

They are informal or proposed labels, not diagnoses. Neither the DSM-5 nor ICD-11 uses them; both describe the person with levels, specifiers or subcodes instead.⁠^3,4,8 Here is what each term usually means and where it stands.⁠^8,9

Why do many clinicians avoid functioning labels?

Because they predict poorly and can cost people support. Autistic people have argued against the labels as stigmatizing and as an inaccurate reflection of their experience; functioning can vary across time and context; and people labeled high functioning may not get the support they need, while those labeled low functioning are underestimated.⁠⁸ In a 2020 study of 2,225 autistic children and teenagers, IQ was a weak predictor of everyday adaptive skills, and the authors concluded “high functioning autism” should be abandoned in research and clinical practice.⁠⁷

The labels are also unpopular with the people they describe. A survey cited in a 2021 review found about 20% of respondents endorsed “high-functioning” autism and fewer than 10% “low-functioning.”⁠⁸ Describing the specific support a person needs, in which setting, says more than either label.⁠^1,8

Read nextHigh-functioning autismLow-functioning autismAutistic burnout

What is profound autism?

A proposed term, not a diagnosis. In 2021 a Lancet Commission proposed “profound autism” to draw attention to autistic people whose needs require lifelong, round-the-clock care, defined at first as autism with an IQ below 50 or being nonverbal or minimally verbal.⁠^9,36

Using that first definition, 26.7% of autistic 8-year-olds in CDC’s network from 2000 to 2016 had profound autism.⁠³⁶ With an updated definition, 16.5% of 7,084 autistic 8-year-olds in 2022 met it and another 32.1% met one part of it, though the assessments needed were missing almost half the time.⁠³⁰

The term is debated. Its supporters say describing this group is critical for planning the services and supports it needs; a critic argues that support should be planned from each person’s goals and needs, not from speech or IQ scores.⁠^31,36

What does nonspeaking autism mean?

It describes autistic people who use little or no spoken language. About 30% of autistic children remain minimally verbal even after years of intervention and education.⁠³²

Some autistic advocates prefer “nonspeaking” to “nonverbal.” As one 2023 commentary puts it, “nonverbal” falsely implies that people who have difficulty producing speech do not understand and cannot use language.⁠³¹ ICD-11 records the same difference with its functional language subcodes.⁠⁴

Read nextNonverbal autismGestalt language processingPathological demand avoidance

What is social (pragmatic) communication disorder?

Social (pragmatic) communication disorder (SCD) is a separate DSM-5 diagnosis for persistent difficulty using verbal and nonverbal language for social purposes, without the restricted, repetitive behaviors that autism also requires.⁠³⁷ It is not a type of autism.⁠³⁷

The DSM-5 says people with marked social communication deficits whose symptoms do not otherwise meet the autism criteria should be evaluated for it.⁠³ SCD cannot be diagnosed together with autism, and ASHA advises considering it only after autism has been ruled out.⁠³⁷

ICD-11 has a close counterpart, developmental language disorder with impairment of mainly pragmatic language, for marked difficulty understanding and using language in social situations, such as making inferences or understanding humor; it is not used when autism explains the difficulty better.⁠³⁸

RelatedSpeech therapyFind a speech therapist

Is there a female type of autism?

No. There is no separate female type in either manual; girls and women are diagnosed with the same autism spectrum disorder, using the same criteria.⁠^3,4 What research does show is that autism may look different in some girls and is more often missed in them.⁠^4,13

Boys are diagnosed far more often. In CDC’s 2022 surveillance, autism was 3.4 times as common among 8-year-old boys as girls, and ICD-11 notes that males are four times more likely to be diagnosed.⁠^4,18 A 2017 meta-analysis of 54 studies concluded the true ratio is closer to 3 to 1, and that girls who meet the criteria are at disproportionate risk of not receiving a diagnosis.⁠¹⁰

ICD-11 describes some of the differences: girls tend to show fewer restricted, repetitive behaviors, and those who are diagnosed more often also have an intellectual disability, which suggests milder presentations in girls may go undetected.⁠⁴ A 2021 review notes there is still reason to suspect girls are missed or diagnosed later more often than boys.⁠¹³

What is autistic masking or camouflaging?

Camouflaging, which includes masking, is a learned coping strategy in which an autistic person hides autistic behavior that might be judged socially unacceptable or performs typical social behavior, sometimes without realizing it.⁠¹ ASHA notes that all genders camouflage but autistic females are more likely to, and that camouflaging may be one reason people are diagnosed later in life.⁠¹

It has a cost. ICD-11 says a diagnosis is still appropriate when exceptional effort hides a person’s difficulties, and that such sustained effort, which may be more typical of females, can harm mental health and well-being.⁠⁴ A 2021 systematic review of 29 studies found higher self-reported camouflaging linked to worse mental health, though the research is too limited to apply to all autistic people.⁠³⁹

The idea is still being tested: a 2021 review of the diagnosis notes that the validity and the gender specificity of camouflaging have been challenged.⁠¹³

In adolescence and adulthood, ICD-11 notes, depression is often a presenting feature of autism, and ASHA links higher camouflaging with stress, anxiety and depression.⁠^1,4

Did scientists find four types of autism in 2025?

A 2025 study did group autistic children into four classes, but they are research groupings, not new diagnoses. Using questionnaire and developmental data on 5,392 autistic children in the SPARK study, researchers identified four classes and linked each to different genetic patterns.⁠¹⁴

• Social and behavioral

  Core autistic traits plus behavior, attention and anxiety difficulties, without developmental delays; 1,976 children.⁠¹⁴

• Mixed, with developmental delay

  Strong developmental delays with a more mixed pattern of other traits; 1,002 children.⁠¹⁴

• Moderate challenges

  Fewer difficulties than other autistic children across all measured areas; 1,860 children.⁠¹⁴

• Broadly affected

  More difficulties than other autistic children across all measured areas; 554 children.⁠¹⁴

The authors note limits: the data were self-reported questionnaires, which may have introduced rater effects, and intellectual disability is a known confounder in assessing social behaviors.⁠¹⁴ Neither the DSM-5-TR nor ICD-11 uses these classes; a diagnosis is still autism spectrum disorder.⁠^1,4

How is autism diagnosed today?

Through a professional evaluation of development and behavior. There is no medical test, such as a blood test; doctors look at the child’s developmental history and behavior, and no single screening or diagnostic tool should be the only basis for the diagnosis.⁠^3,21

1. Monitoring. Parents and providers watch milestones at every well visit.⁠²¹
2. Screening. The American Academy of Pediatrics recommends autism screening for all children at 18 and 24 months, and at other times if there is a concern.⁠²¹
3. Formal evaluation. One or more specialists, such as a developmental pediatrician, child psychologist, speech-language pathologist or occupational therapist, look in depth at development.⁠²¹
4. Diagnosis. By age 2, a diagnosis by an experienced professional can be considered reliable, though many children are diagnosed much later.⁠²¹

CDC lists developmental pediatricians, child neurologists, and child psychologists or psychiatrists among the specialists who can do an in-depth evaluation and make a diagnosis.⁠¹⁶ You can also ask your state’s public early childhood system for a free evaluation, or your local public school system if your child is 3 or older, without waiting for a doctor’s referral or a medical diagnosis.⁠¹⁶

The clinician decides whether the criteria for autism spectrum disorder are met, then describes the person with a support level for each area and any specifiers, or, in ICD-11, the intellectual development and functional language subcode.⁠^3,4

When should you talk to your child’s doctor about autism?

When your child is not meeting milestones, CDC advises talking with your doctor or nurse and asking about developmental screening, and contacting the doctor with any concern about development.⁠^16,21 Examples CDC lists include using few or no gestures by 12 months and not pointing to show you something interesting by 18 months.⁠²⁰

Do not wait if your child loses words, play or social skills they had: contact their doctor promptly.⁠^4,16

Not sure where to start?Does my child need an evaluation?Autism or auditory processing? QuizFind a therapist near you

How do adults get diagnosed with autism?

By asking a health care provider for a referral for an autism evaluation, usually with a neuropsychologist, psychologist or psychiatrist who has experience with autism.⁠¹⁵ Adult diagnosis is often harder, because some autism symptoms overlap with those of anxiety disorders or ADHD.⁠¹⁵

Being diagnosed late is common: WHO notes that autism is often not diagnosed until much later than its first signs, and some autistic people are not diagnosed until later school age, adolescence or adulthood. ICD-11 adds that autism can first come to clinical attention at any age, though it is lifelong.⁠^1,4,17

What does an old autism diagnosis mean now?

It still means autism. The DSM-5 directs that anyone with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder or PDD-NOS “should be given the diagnosis of autism spectrum disorder.”⁠³ WHO’s map does the same for ICD-10’s childhood autism, atypical autism and Asperger syndrome.⁠⁶

The change in manuals is not by itself a reason to be re-evaluated.⁠³ In a 2012 study, the DSM-5 criteria identified 91% of children with clinical DSM-IV diagnoses, though the APA notes that several other studies were inconsistent.⁠² The American Psychiatric Association adds that anyone with one of the four old diagnoses should meet the autism criteria “or another, more accurate DSM-5 diagnosis,” such as social (pragmatic) communication disorder.⁠^2,3

A new evaluation can still help when you need a current picture: support levels, specifiers and ICD-11 subcodes did not exist when older reports were written.⁠^3,4

Read nextWhat an old atypical autism or PDD-NOS diagnosis means

How common is autism?

About 1 in 31 (3.2%) 8-year-olds in the US had been identified with autism spectrum disorder in CDC’s most recent surveillance, and autism is over three times more common in boys than in girls.⁠⁴¹ Worldwide, WHO estimates that about 1 in 127 people had autism in 2021, an average figure with wide variation between studies.⁠¹⁷

Many autistic people are diagnosed late. WHO notes that the characteristics may be detected in early childhood, but autism is often not diagnosed until much later.⁠¹⁷

Where does sensory processing fit in autism?

Sensory differences are part of the autism diagnosis in both current manuals. The DSM-5 counts hyper- or hyporeactivity to sensory input as one of the four kinds of restricted, repetitive behavior, and ICD-11 lists lifelong hypersensitivity or hyposensitivity to sensory stimuli, or unusual interest in them.⁠^3,4

In young children, sensory reactions can be what parents notice first. ICD-11 notes that in preschoolers, sensitivities to everyday sounds or foods may overshadow the social communication differences underneath.⁠⁴ Occupational therapy can address everyday skills and activities of daily living, and an occupational therapist may be one of the specialists in a formal developmental evaluation.⁠^21,42

RelatedSensory processing and autismMonotropismSensory processing differencesOccupational therapyFind an occupational therapist

Related on DrSensory

• Autism

  Signs, diagnosis and support for families.

• Atypical autism

  The ICD-10 diagnosis F84.1, PDD-NOS, and what an old label means now.

• Classic autism

  What the older term meant and where it stands today.

• Asperger’s syndrome

  Why it was removed from the DSM-5, and why some people keep the name.

• PDD-NOS

  The DSM-IV catch-all category and what replaced it.

• Childhood disintegrative disorder

  The rare pattern of skill loss after typical development.

• High-functioning autism

  What the label describes, and why it is changing.

• Low-functioning autism

  The DSM-5 levels and ICD-11 codes that replaced it, and profound autism.

• Nonverbal autism

  Nonspeaking autistic children, communication and AAC.

• Sensory processing and autism

  How sensory differences show up in autism.

• Pathological demand avoidance

  The proposed profile and the debate around it.

• Autistic burnout

  Exhaustion, loss of skills and what helps.

Sources

1. American Speech-Language-Hearing Association. Autism (Practice Portal). Checked October 22, 2026.
   Show the passageHide the passage

   “The most notable change eliminated the Pervasive Developmental Disorder (PDD) category, which included diagnoses of Autistic Disorder, Asperger’s Disorder, Childhood Disintegrative Disorder, Rett’s Disorder, and Pervasive Developmental Disorder Not Otherwise Specified”; the DSM-5-TR criteria “no longer specify subtypes”; “The DSM-5-TR lists Rett syndrome, a genetic disorder, as a separate diagnosis in which disruptions of social interaction may be observed during the regressive phase”; “Levels of support may vary by context and may fluctuate over time”; “While severity rating is included in the diagnosis, it should not be used to determine eligibility for any service”; “Some autistic people are not diagnosed until later school age, adolescence, or even adulthood”; “Camouflaging may be another potential reason why people are diagnosed with autism later in life”; camouflaging “is a learned coping strategy that autistic people use to (a) hide their autistic behavior that might be deemed socially unacceptable”; “Autistic people may camouflage but may not realize that they are doing it”; “All genders can camouflage, but autistic females are more likely to camouflage and mask their autistic traits”; “Higher camouflaging has been associated with excessive stress, anxiety, and depression”.
2. American Psychiatric Association. Autism Spectrum Disorder (DSM-5 fact sheet). 2013. Checked October 22, 2026.
   Show the passageHide the passage

   “Using DSM-IV, patients could be diagnosed with four separate disorders: autistic disorder, Asperger’s disorder, childhood disintegrative disorder, or the catch-all diagnosis of pervasive developmental disorder not otherwise specified”; “Researchers found that these separate diagnoses were not consistently applied across different clinics and treatment centers”; “Anyone diagnosed with one of the four pervasive developmental disorders (PDD) from DSM-IV should still meet the criteria for ASD in DSM-5 or another, more accurate DSM-5 diagnosis”; “the symptoms of people with ASD will fall on a continuum, with some individuals showing mild symptoms and others having much more severe symptoms”; the Huerta 2012 study found “DSM-5 criteria identified 91 percent of children with clinical DSM-IV PDD diagnoses”; “Several other studies, using various methodologies, have been inconsistent in their findings”.
3. Centers for Disease Control and Prevention. Clinical Testing and Diagnosis for Autism Spectrum Disorder. Page dated May 8, 2025. Checked October 22, 2026.
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   The DSM-5 criteria as CDC reproduces them: “a child must have persistent deficits in each of three areas of social communication and interaction” “plus at least two of four types of restricted, repetitive behaviors”; “Hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment”; “Specify current severity”: “For either criterion, severity is described in 3 levels”: “Level 3 – requires very substantial support”, “Level 2 – Requires substantial support”, “Level 1 – requires support”; criterion C: “Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life)”; “Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level”; “Individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger's disorder, or pervasive developmental disorder not otherwise specified should be given the diagnosis of autism spectrum disorder”; “Individuals who have marked deficits in social communication, but whose symptoms do not otherwise meet criteria for autism spectrum disorder, should be evaluated for social (pragmatic) communication disorder”; specifiers “With or without accompanying intellectual impairment”, “With or without accompanying language impairment”, “Associated with a known medical or genetic condition or environmental factor”, “Associated with another neurodevelopmental, mental, or behavioral disorder” and “With catatonia”; “no single tool should be used as the basis for diagnosis”.
4. World Health Organization. 6A02 Autism spectrum disorder. ICD-11 for Mortality and Morbidity Statistics, release 2026-01, with diagnostic requirements. Checked October 22, 2026.
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   “persistent deficits in the ability to initiate and to sustain reciprocal social interaction and social communication”; “Individuals along the spectrum exhibit a full range of intellectual functioning and language abilities”; Rett syndrome (LD90.4) is among its exclusions; “Lifelong excessive and persistent hypersensitivity or hyposensitivity to sensory stimuli or unusual interest in a sensory stimulus”; “If present, a separate diagnosis of Disorder of Intellectual Development should be assigned, using the appropriate category to designate severity (i.e., Mild, Moderate, Severe, Profound, Provisional)”; “Functional language refers to the capacity of the individual to use language for instrumental purposes (e.g., to express personal needs and desires)”; “with impaired functional language (i.e., not able to use more than single words or simple phrases)”; “6A02.Y Other Specified Autism Spectrum Disorder can be used if the above parameters do not apply”; “6A02.Z Autism Spectrum Disorder, Unspecified can be used if the above parameters are unknown”; “A qualifier is also provided for loss of previously acquired skills, which is a feature of the developmental history of a small proportion of individuals with Autism Spectrum Disorder”; “This regression typically occurs during the second year of life and most often involves language use and social responsiveness”; “Loss of previously acquired skills is rarely observed after 3 years of age”; “6A02.x0 without loss of previously acquired skills”; “6A02.x1 with loss of previously acquired skills”; “Some individuals with Autism Spectrum Disorder are able to function adequately in many contexts through exceptional effort, such that their deficits may not be apparent to others. A diagnosis of Autism Spectrum Disorder is still appropriate in such cases”; “Such sustained effort, which may be more typical of affected females, can have a deleterious impact on mental health and well-being”; “During adolescence and adulthood, Depressive Disorders are often a presenting feature”; “Catatonic states have also been described”; “Sensory sensitivities to everyday sounds, or to foods, may overshadow the underlying social communication deficits”; “Although Autism Spectrum Disorder can present clinically at all ages, including during adulthood, it is a lifelong disorder”; “Males are four times more likely than females to be diagnosed with Autism Spectrum Disorder”; “Females diagnosed with Autism Spectrum Disorder are more frequently diagnosed with co-occurring Disorders of Intellectual Development, suggesting that less severe presentations may go undetected as compared to males”; “Females tend to demonstrate fewer restricted, repetitive interests and behaviours than males”; “individuals with Attention Deficit Hyperactivity Disorder do not exhibit the persistent deficits in initiating and sustaining social communication and reciprocal social interactions or the persistent restricted, repetitive, and inflexible patterns of behaviour, interests, or activities that are the defining features of Autism Spectrum Disorder”; “Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder can co-occur and both diagnoses may be assigned if diagnostic requirements are met for each”; conditions with regression such as “acquired epileptic aphasia or Landau Kleffner syndrome, autoimmune encephalitis, Rett Syndrome” are differentiated from autism.
5. Lord C, Petkova E, Hus V, et al. A multisite study of the clinical diagnosis of different autism spectrum disorders. Archives of General Psychiatry. 2012;69(3):306–313. doi:10.1001/archgenpsychiatry.2011.148 (PMID 22065253; PMC3626112). Checked October 22, 2026.
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   2,102 children and teenagers aged 4 to 18 at 12 university-based sites; “Although distributions of scores on standardized measures were similar across sites, significant site differences emerged in best-estimate clinical diagnoses of specific autism spectrum disorders”; “Clinical distinctions among categorical diagnostic subtypes of autism spectrum disorders were not reliable even across sites with well-documented fidelity using standardized diagnostic instruments”.
6. World Health Organization. ICD-10 to ICD-11 mapping tables, release 2026-01 (10To11MapToOneCategory). Checked October 22, 2026.
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   F84.0 Childhood autism and F84.1 Atypical autism map to 6A02.Z “Autism spectrum disorder, unspecified”; F84.5 Asperger syndrome to 6A02.0 “Autism spectrum disorder without disorder of intellectual development and with mild or no impairment of functional language”; F84.2 Rett syndrome to LD90.4, in chapter 20, “Developmental anomalies”; F84.3 Other childhood disintegrative disorder, F84.4, F84.8 and F84.9 to 6A0Z “Neurodevelopmental disorders, unspecified”.
7. Alvares GA, Bebbington K, Cleary D, et al. The misnomer of ‘high functioning autism’: intelligence is an imprecise predictor of functional abilities at diagnosis. Autism. 2020;24(1):221–232. doi:10.1177/1362361319852831 (PMID 31215791). Checked October 22, 2026.
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   “is a term often used for individuals with autism spectrum disorder without an intellectual disability”; in 2,225 children aged 1 to 18, “intelligence quotient was a weak predictor of Vineland Adaptive Behaviour Scales after controlling for sex”; “this term should be abandoned in research and clinical practice”.
8. Bottema-Beutel K, Kapp SK, Lester JN, Sasson NJ, Hand BN. Avoiding ableist language: suggestions for autism researchers. Autism in Adulthood. 2021;3(1):18–29. doi:10.1089/aut.2020.0014 (PMID 36601265; PMC8992888). Checked October 22, 2026.
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   “Autistic people without ID are sometimes referred to as “high-functioning,” with the assumption that these individuals will function better than autistic individuals with ID (often referred to as “low functioning”)”; “Autistic people have argued against the use of these labels both because they are stigmatizing, and because they inaccurately reflect their experience”; “Functioning can also vary across time and context and may depend more on the adequacy of supports provided than on the presence or absence of ID”; “they can also result in situations where autistic people labeled “high functioning” are not provided with the supports they need, while autistic people labeled “low functioning” are underestimated in regard to their actual capabilities”; “We encourage researchers to replace terms such as “high-” and “low-functioning” with descriptors of the characteristics they intend to convey”; citing a survey, few endorse ““high-functioning” autism (approximately 20% endorse) and “low-functioning” autism (<10% endorse)”.
9. Siegel M, Lord CL, Tager-Flusberg H, Ursitti J, Halladay A, Singer AT. Developing a consensus research definition for profound autism using a modified Delphi method. Molecular Autism. 2026;17(1):28. doi:10.1186/s13229-026-00727-y (PMID 42380932; PMC13326320). Checked October 22, 2026.
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   “In 2021, the administrative term Profound Autism (PA) was proposed by a Lancet Commission to draw attention to autistic people whose impairments require lifelong, round-the-clock care”; “76% of the respondents agreed on a research definition of PA”.
10. Loomes R, Hull L, Mandy WPL. What is the male-to-female ratio in autism spectrum disorder? A systematic review and meta-analysis. Journal of the American Academy of Child and Adolescent Psychiatry. 2017;56(6):466–474. doi:10.1016/j.jaac.2017.03.013 (PMID 28545751). Checked October 22, 2026.
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    “Fifty-four studies were analyzed, with 13,784,284 participants, of whom 53,712 had ASD”; “Of children meeting criteria for ASD, the true male-to-female ratio is not 4:1, as is often assumed; rather, it is closer to 3:1”; “There appears to be a diagnostic gender bias, meaning that girls who meet criteria for ASD are at disproportionate risk of not receiving a clinical diagnosis”.
11. World Health Organization. International Classification of Diseases (ICD). “ICD-11, was adopted by the 72nd World Health Assembly in 2019 and came into effect on 1st January 2022”; for ICD-10, “into effect 1 Jan 1993 adopted May 1990”. Checked October 22, 2026.
12. Reed GM, First MB, Kogan CS, et al. Innovations and changes in the ICD-11 classification of mental, behavioural and neurodevelopmental disorders. World Psychiatry. 2019;18(1):3–19. doi:10.1002/wps.20611 (PMID 30600616; PMC6313247). Checked October 22, 2026.
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    “Autism spectrum disorder in the ICD‐11 incorporates both childhood autism and Asperger's syndrome from the ICD‐10 under a single category”; “Qualifiers are provided for the extent of impairment in intellectual functioning and functional language abilities”.
13. Rosen NE, Lord C, Volkmar FR. The diagnosis of autism: from Kanner to DSM-III to DSM-5 and beyond. Journal of Autism and Developmental Disorders. 2021;51(12):4253–4270. doi:10.1007/s10803-021-04904-1 (PMID 33624215; PMC8531066). Checked October 22, 2026.
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    “the definition of autism has in fact alternated over time between broader and narrower views of the condition”; Leo Kanner, 1943, “described 11 children, 8 boys and 3 girls”; Hans Asperger’s 1944 report “of boys who had marked social difficulties, unusual circumscribed interests, and good verbal skills”; “autism was included for the first time in DSM-III (APA 1980)”; “A significant conceptual change in DSM-III-R was the move from “infantile autism” to “autistic disorder” as the name for the condition”; in DSM-III-R “the ‘residual’ or ‘subthreshold’ category was labeled pervasive developmental disorder not otherwise specified (PDD-NOS)”; “In ICD-10, the decision was made to explicitly recognize other disorders, including Asperger syndrome, Rett’s disorder, and childhood disintegrative disorder”; “DSM-IV’s diagnostic subcategories (autistic disorder, Asperger’s disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), Rett’s disorder, and childhood disintegrative disorder) were located within the Pervasive Developmental Disorders (PDDs) classification”; the shift to one diagnosis was driven by findings of “variability in the number and severity of ASD symptoms within and between diagnostic subgroups with similar core symptom profiles”, “poor predictive power of subcategories on later outcomes”, “poor diagnostic clarity resulting in limited reliability in assigning subcategory diagnoses” and “restrictions on treatment eligibility and coverage based on subtypes”; “concerns over the removal of an important part of an individual’s identity and community, specifically related to Asperger’s disorder”; “the evidence for the existence of subcategories within ASD has continued to be very weak”; “the severity metric has shown questionable validity”; “there is still reason to suspect that females are missed or delayed in diagnosis more often than males”; “although the validity (Fombonne 2020) and the gender specificity (Frazier and Hardan 2017) of the ‘camouflage’ construct have been challenged”; DSM-III placed autism “in an entirely new ‘class’ of conditions”, the pervasive developmental disorders.
14. Litman A, Sauerwald N, Green Snyder L, et al. Decomposition of phenotypic heterogeneity in autism reveals underlying genetic programs. Nature Genetics. 2025;57(7):1611–1619. doi:10.1038/s41588-025-02224-z (PMID 40634707; PMC12283356). Checked October 22, 2026.
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    “we identified 239 item-level and composite phenotype features present in 5,392 individuals from the SPARK cohort”; “We identified one class that demonstrated high scores (greater difficulties) across core autism categories of social communication and restricted and/or repetitive behaviors compared to other autistic children, as well as disruptive behavior, attention deficit and anxiety, but no reports of developmental delays”; “Individuals in the last two classes scored consistently lower (fewer difficulties) and consistently higher than other autistic children across all seven categories”; classes “Social/behavioral ( n = 1,976)”, “Mixed ASD with DD ( n = 1,002)”, “Moderate challenges ( n = 1,860) and Broadly affected ( n = 554)”; “The reliance on self-reported data, however, may have introduced rater effects, and intellectual disability is a known confounder in assessing social behaviors”.
15. National Institute of Mental Health. Autism Spectrum Disorder. NIH Publication No. 25-MH-8084, revised 2025. Checked October 22, 2026.
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    Autism is called a spectrum disorder “because people with autism have a range of characteristics, needs, strengths, and challenges”; the DSM-5 is “a guide created by the American Psychiatric Association that health care providers use to diagnose mental disorders and developmental disorders”; “Diagnosing ASD in adults is often more difficult than diagnosing ASD in children”; “In adults, some ASD symptoms can overlap with symptoms of mental disorders such as an anxiety disorder or attention-deficit/hyperactivity disorder (ADHD)”; “Adults who have questions about whether they may be on the autism spectrum should talk with a health care provider and ask for a referral for an ASD evaluation”; “adults can be referred to a neuropsychologist, psychologist, or psychiatrist who has experience with ASD”.
16. Centers for Disease Control and Prevention. About Autism Spectrum Disorder. Checked October 22, 2026.
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    “Autism spectrum disorder (ASD) is a developmental disability caused by differences in the brain”; “some people with ASD may have advanced conversation skills whereas others may be nonverbal”; “Some people with ASD need a lot of help in their daily lives; others can work and live with little to no support”; “Some children with ASD gain new skills and meet developmental milestones until around 18 to 24 months of age, and then they stop gaining new skills or lose the skills they once had”; “There is not just one cause of ASD”; “Contact your child's doctor if you have any concerns about your child's development”; “Specialists who can do a more in-depth evaluation and make a diagnosis include” developmental pediatricians, child neurologists, and child psychologists or psychiatrists; “call your state's public early childhood system to request a free evaluation”; “You do not need to wait for a doctor's referral or a medical diagnosis to make this call”; “If your child is 3 years old or older, contact your local public school system”.
17. World Health Organization. Autism (fact sheet). Checked October 22, 2026.
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    “It is estimated that worldwide in 2021 about 1 in 127 persons had autism”; “The abilities and needs of autistic people vary and can evolve over time”; “This estimate represents an average figure, and reported prevalence varies substantially across studies”; “The level of intellectual functioning among autistic people varies widely, extending from profound impairment to superior levels”; “Characteristics of autism may be detected in early childhood, but autism is often not diagnosed until much later”.
18. Shaw KA, Williams S, Patrick ME, et al. Prevalence and early identification of autism spectrum disorder among children aged 4 and 8 years: Autism and Developmental Disabilities Monitoring Network, 16 sites, United States, 2022. MMWR Surveillance Summaries. 2025;74(No. SS-2):1–22. doi:10.15585/mmwr.ss7402a1. Checked October 22, 2026.
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    “ASD prevalence was 32.2 per 1,000 children (one in 31) across the 16 sites”; “ASD was 3.4 times as prevalent among boys (49.2) than girls (14.3)”; among children with cognitive data, “39.6% were classified as having intellectual disability (IQ ≤70) at their most recent test or examination, 24.2% were classified in the borderline range (IQ = 71–85), and 36.1% were classified in the average or higher range (IQ >85)”.
19. NHS. What is autism?. Page last reviewed May 6, 2026. “You might also hear autism called autism spectrum disorder (ASD). This is the medical term for a diagnosis of autism”; “Autism is a difference in how your brain develops that affects how you see and experience the world”; “It’s not an illness”. Checked October 22, 2026.
20. Centers for Disease Control and Prevention. Signs and Symptoms of Autism Spectrum Disorder. Checked October 22, 2026.
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    “People with ASD often have problems with social communication and interaction, and restricted or repetitive behaviors or interests”; examples include “Uses few or no gestures by 12 months of age (for example, does not wave goodbye)”, “Does not point to show you something interesting by 18 months of age”, “Lines up toys or other objects and gets upset when order is changed”, “Repeats words or phrases over and over (called echolalia)” and “Has unusual reactions to the way things sound, smell, taste, look, or feel”; “children with ASD may not have all or any of the behaviors listed as examples here”.
21. Centers for Disease Control and Prevention. Screening for Autism Spectrum Disorder. Checked October 22, 2026.
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    “there is no medical test, such as a blood test, to diagnose the disorder”; “Doctors look at the child's developmental history and behavior to make a diagnosis”; the AAP recommends screening specifically for autism at “18 months” and “24 months”; “By age 2, a diagnosis by an experienced professional can be considered reliable”; “However, many children do not receive a final diagnosis until they are much older”; “Screening at times other than the recommended ages should be done if you or your doctor have a concern”; a formal evaluation is done by “one or more trained specialists such as a developmental pediatrician, child psychologist, speech-language pathologist, and/or occupational therapist”; “If you notice that your child is not meeting milestones, talk with your doctor or nurse about your concerns and ask about developmental screening”; “A diagnosis of ASD now includes several conditions that used to be diagnosed separately: autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), and Asperger syndrome”; “Some people with ASD are not diagnosed until they are adolescents or adults”.
22. World Health Organization. F84 Pervasive developmental disorders. International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10), version 2019. Checked October 22, 2026.
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    F84: “A group of disorders characterized by qualitative abnormalities in reciprocal social interactions and in patterns of communication, and by a restricted, stereotyped, repetitive repertoire of interests and activities”. F84.0 childhood autism: “the presence of abnormal or impaired development that is manifest before the age of three years” in “all the three areas of psychopathology: reciprocal social interaction, communication, and restricted, stereotyped, repetitive behaviour”, including “Kanner syndrome”. F84.1 atypical autism: “differs from childhood autism either in age of onset or in failing to fulfil all three sets of diagnostic criteria”. F84.2 Rett syndrome: “apparently normal early development is followed by partial or complete loss of speech and of skills in locomotion and use of hands, together with deceleration in head growth”. F84.3 other childhood disintegrative disorder: “a period of entirely normal development before the onset of the disorder, followed by a definite loss of previously acquired skills in several areas of development over the course of a few months”, including “Heller syndrome”. F84.4 “Overactive disorder associated with mental retardation and stereotyped movements”: “An ill-defined disorder of uncertain nosological validity”. F84.5 Asperger syndrome: “It differs from autism primarily in the fact that there is no general delay or retardation in language or in cognitive development”.
23. National Institute of Neurological Disorders and Stroke. Rett Syndrome. “Rett syndrome is a neurodevelopmental disorder”; “Rett syndrome most commonly affects girls, although boys are also (rarely) affected”; “Nearly all cases of Rett syndrome are caused by a mutation in the methyl CpG binding protein 2, or MECP2 (pronounced meck-pea-two) gene”. Checked October 22, 2026.
24. Coutelle R, Coulon N, Schröder CM, Putois O. Investigating the borders of autism spectrum disorder: lessons from the former diagnosis of pervasive developmental disorder not otherwise specified. Frontiers in Psychiatry. 2023;14:1149580. doi:10.3389/fpsyt.2023.1149580 (PMID 38173703; PMC10762794). Checked October 22, 2026.
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    “The systematic review included 81 studies comprising 6,644 children with PDD-NOS”; “The PDD-NOS diagnosis category was first introduced in 1987”; “the PDD-NOS category included atypical autism, i.e., presentations that did not meet the criteria for AD because of late age of onset, atypical symptomatology, or subthreshold symptomatology, or all of these”; in CDC data from 2010, “PDD-NOS were 46% of the PDD, AD 43% and AS 11%”; “PDD-NOS corresponds to milder form of autism with less impact and less associated disorder, with the exception of schizophrenia and mood disorder”.
25. Westphal A, Schelinski S, Volkmar F, Pelphrey K. Revisiting regression in autism: Heller’s dementia infantilis. Journal of Autism and Developmental Disorders. 2013;43(2):265–271. doi:10.1007/s10803-012-1559-z (PMID 22677931). Checked October 22, 2026.
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    “Theodor Heller first described a severe regression of adaptive function in normally developing children, something he termed dementia infantilis, over one 100 years ago”; “Dementia infantilis is most closely related to the modern diagnosis, childhood disintegrative disorder”.
26. First MB, Yousif LH, Clarke DE, Wang PS, Gogtay N, Appelbaum PS. DSM-5-TR: overview of what’s new and what’s changed. World Psychiatry. 2022;21(2):218–219. doi:10.1002/wps.20989 (PMID 35524596; PMC9077590). Checked October 22, 2026.
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    “the minimum required number of types of deficits in social communication was ambiguous”; “Since the intention of the DSM‐5 Work Group was always to maintain a high diagnostic threshold by requiring all three, criterion A was revised to be clearer”, to “as manifested by all of the following”.
27. Centers for Disease Control and Prevention, National Center for Health Statistics. ICD-10-CM Files. Checked October 22, 2026.
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    “FY27 ICD-10-CM codes should be used for healthcare services provided from October 1, 2026, through September 30, 2027”. In the FY2027 Tabular List, F84.0 “Autistic disorder” includes “Autism spectrum disorder” and “Kanner's syndrome”; F84.5 “Asperger's syndrome”; F84.9 “Pervasive developmental disorder, unspecified” includes “Atypical autism”.
28. Russell LA, Tinker SC, Shaw KA, et al. Prevalence of autism spectrum disorder severity levels from the fifth edition of the Diagnostic and Statistical Manual (DSM-5) in the Autism and Developmental Disabilities Monitoring Network. Journal of Autism and Developmental Disorders. Published online March 2026. doi:10.1007/s10803-026-07292-6 (PMID 41872583; PMC13267130). Checked October 22, 2026.
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    The DSM-5 “introduced severity level specifiers for autism spectrum disorder (ASD) with minimal description of the criteria for categorizing three levels of severity”; “Less than half (40.4%) of children with documented ASD diagnoses had any severity level specified in their records, with wide variation by site (4.8%-73.2%)”; “Utilization of the DSM-5’s severity levels by community professionals varied widely, limiting their potential utility in identifying needed services and supports for children with ASD”.
29. Vaquerizo-Serrano J, Salazar De Pablo G, Singh J, Santosh P. Catatonia in autism spectrum disorders: a systematic review and meta-analysis. European Psychiatry. 2021;65(1):e4. doi:10.1192/j.eurpsy.2021.2259 (PMID 34906264; PMC8792870). Checked October 22, 2026.
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    “Catatonia, originally described in 1874, is a complex syndrome of abnormal motor, vocal, and behavioral symptoms, with impaired volition and vegetative function”; “DSM-5 defines catatonia as being characterized by the presence of at least three of the following symptoms: catalepsy, waxy flexibility, stupor, mutism, negativism, agitation, posturing, stereotypes, mannerisms, grimacing, echolalia, and echopraxia”; “Symptoms of social indifference, mannerisms, and echolalia are common to both catatonia and ASD”; “The systematic review included 12 studies, seven of which were used for the meta-analysis, comprising 969 individuals”; “The mean age was 21.25 (7.5) years”; “Our meta-analysis showed that 10.4% (5.8–18.0 95%CI) of individuals with ASD have catatonia”.
30. Shaw KA, Russell LA, DiRienzo M, et al. Profound autism prevalence and assessment practices in a population-based study. Journal of the American Academy of Child and Adolescent Psychiatry. Published online October 2026. doi:10.1016/j.jaac.2026.09.019 (PMID 42826765). Checked October 22, 2026.
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    “Profound autism is a proposed subcategory of autism including individuals unable to meet basic daily adaptive needs and requiring 24-hour care”; among 7,084 autistic 8-year-olds in 2022, “Of children with autism, 16.5% met the updated profound autism definition and 32.1% met one element of the definition but did not meet full criteria”; “Adaptive or other assessments underlying the profound autism definition were missing almost half the time”.
31. Kripke-Ludwig R. “Profound Autism” label does not predict strengths or help plan supports. Public Health Reports. 2023;138(6):849–850. doi:10.1177/00333549231199480 (PMID 37732335; PMC10576471). Checked October 22, 2026.
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    “The term “nonverbal” comes from the Latin verbum, which means “a word” or “language” and falsely implies that people who have sensory–motor difficulties with producing speech do not understand and cannot use language”; “Person-centered planning is based on goals and needs, not on speech abilities or IQ scores”.
32. Tager-Flusberg H, Kasari C. Minimally verbal school-aged children with autism spectrum disorder: the neglected end of the spectrum. Autism Research. 2013;6(6):468–478. doi:10.1002/aur.1329 (PMID 24124067; PMC3869868). “It is currently estimated that about 30% of children with autism spectrum disorder remain minimally verbal, even after receiving years of interventions and a range of educational opportunities”. Checked October 22, 2026.
33. Treffert DA. The savant syndrome: an extraordinary condition. A synopsis: past, present, future. Philosophical Transactions of the Royal Society B. 2009;364(1522):1351–1357. doi:10.1098/rstb.2008.0326 (PMID 19528017; PMC2677584). Checked October 22, 2026.
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    “As many as one in 10 persons with autistic disorder have such remarkable abilities in varying degrees, although savant syndrome occurs in other developmental disabilities or in other types of central nervous system injury or disease as well”.
34. Malik O, Baird G. Commentary: PDA, what’s in a name? Dimensions of difficulty in children reported to have an ASD and features of extreme/pathological demand avoidance. Child and Adolescent Mental Health. 2018;23(4):387–388. doi:10.1111/camh.12273 (PMID 32677136). Checked October 22, 2026.
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    PDA “refers to a collection of behaviours that children will demonstrate to avoid instructions (and tasks) that they perceive as demands”; “PDA features are commonly encountered in children with autism but PDA is not a subtype of autism nor a separately diagnosed mental, behavioural or developmental disorder in any of the major classification systems (ICD-10 or DSM-5)”.
35. Kildahl AN, Helverschou SB, Rysstad AL, et al. Pathological demand avoidance in children and adolescents: a systematic review. Autism. 2021;25(8):2162–2176. doi:10.1177/13623613211034382 (PMID 34320869). Checked October 22, 2026.
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    “Requests for diagnoses of pathological demand avoidance have increased over recent years, but pathological demand avoidance remains a controversial issue”; “Problems concerning definition and measurement in the reviewed studies currently limit any conclusions regarding the uniformity or stability of the behaviours described”.
36. Hughes MM, Shaw KA, DiRienzo M, et al. The prevalence and characteristics of children with profound autism, 15 sites, United States, 2000–2016. Public Health Reports. 2023;138(6):971–980. doi:10.1177/00333549231163551 (PMID 37074176; PMC10576490). Checked October 22, 2026.
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    “A recent Lancet commission defined “profound autism” as having autism with an overall or subdomain intelligence quotient (IQ) score <50 or being nonverbal or minimally verbal”; “The percentage of 8-year-old children with profound autism among those with autism was 26.7%”; “the definition of profound autism may evolve”; “describing and quantifying the profound autism population is critical for planning to ensure this group receives the services and supports needed during the life course”.
37. American Speech-Language-Hearing Association. Social Communication Disorder (Practice Portal). Checked October 22, 2026.
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    “Social communication disorder (SCD) is characterized by persistent difficulties with the use of verbal and nonverbal language for social purposes”; “In the case of autism spectrum disorder, social communication problems are a defining feature, along with restricted, repetitive patterns of behavior”; “SCD cannot be diagnosed in conjunction with autism spectrum disorder”; “SCD should be considered after ruling out ASD as a potential diagnosis”.
38. World Health Organization. 6A01.22 Developmental language disorder with impairment of mainly pragmatic language. ICD-11 for Mortality and Morbidity Statistics, release 2026-01. Checked October 22, 2026.
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    “persistent and marked difficulties with the understanding and use of language in social contexts, for example making inferences, understanding verbal humour, and resolving ambiguous meaning”; “This qualifier should not be used if the pragmatic language impairment is better explained by Autism Spectrum Disorder”.
39. Cook J, Hull L, Crane L, Mandy W. Camouflaging in autism: a systematic review. Clinical Psychology Review. 2021;89:102080. doi:10.1016/j.cpr.2021.102080 (PMID 34563942). Checked October 22, 2026.
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    29 studies; “sex and gender differences exist in camouflaging”; “higher self-reported camouflaging is associated with worse mental health outcomes”; “the research base was limited regarding participant characterisation and representativeness, which suggests that conclusions cannot be applied to the autistic community as a whole”.
40. National Institute of Mental Health. Autism Spectrum Disorder (health topic). “If you or someone you know is struggling or having thoughts of suicide, call or text the 988 Suicide & Crisis Lifeline at 988 or chat at 988lifeline.org”. Checked October 22, 2026.
41. Centers for Disease Control and Prevention. Data and Statistics on Autism Spectrum Disorder. “About 1 in 31 (3.2%) children aged 8 years has been identified with ASD according to estimates from CDC's ADDM Network”; “ASD is over 3 times more common among boys than among girls”. Checked October 22, 2026.
42. American Psychiatric Association. What Is Autism Spectrum Disorder?. Checked October 22, 2026.
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    “People with certain specific genetic conditions such as Fragile X Syndrome and Tuberous Sclerosis are at increased risk for being diagnosed with autism”; “These two conditions together with hundreds of individually rare genetic causes for autism explain over 30% of cases”; “Having a sibling with autism also increases the likelihood of a child being diagnosed with autism”; “Vaccines on the other hand have not been shown to increase the likelihood of an autism diagnosis”; occupational therapy “Can address adaptive skills deficits with activities of daily living, as well as problems with handwriting”.
43. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR). “DSM-5-TR is the standard classification of mental disorders used by mental health professionals in the United States”; the Future DSM Navigator gives “regularly updated information relevant to the development of the Future DSM”. Checked October 22, 2026.

Medical disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your child. If you are worried about immediate safety, call or text 988 (US). If your child has lost skills they previously had, contact their doctor promptly.