Different Types of Autism Spectrum Disorders

Different types of autism spectrum disorders can be identified in the autistic children depending upon the criteria and severity of their autistic features. The researchers found out 5 different types of autism spectrum disorders which are Asperger’s Syndrome, Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), Autistic Disorders, Childhood Disintegrative Disorders (CDD) and Rett’s Syndrome. These different types of autism were shown in the fourth version of Diagnostic and Statistic Manual until May 2013.

Mahi in article Types of Autism

All these different types of autism possess different characteristics which might be sometimes similar in nature but vary in severity. As such, it is very difficult to identify each type of autism without acquiring in-depth knowledge of it or the help of the specialist. The different types of autism spectrum disorder help in proper diagnosis and timely intervention in the development of the autistic children. If we can diagnose proper types of autism in our child it will help us in taking his/her care and timely application of the therapies to bring significant development.

In this article, I would like to discuss the different types of autism spectrum disorders which is mentioned in the beginning of this article. It will help the parents, caregivers, teachers, and therapist to handle the child in a most effective manner.

Here, I would also like to discuss the present classification of different types of autism through Diagnostic and Statistical Manual (DSM-5).

Asperger’s Syndrome

Hans AspergerHans Asperger, an Austrian Pediatrician first published the definition of Asperger’s Syndrome during the 2nd WW in 1944. The individuals with this type of autism possess a few of the autistic features. A person with Asperger’s syndrome may be very intelligent and able to handle his/her daily life. Generally, they do not have problems with language or intellectual disability. They possess average or above average intellect. They develop language skills close to normal but have problems with social and communication skills. Some researchers say that the great scientist Einstein might have this type of autism.

In addition to the above-mentioned features, the individuals affected with Asperger’s syndrome might have all or some of the following disabilities:

  • It is high functioning autism spectrum disorders.
  • They face emotional and social challenges.
  • Show unusual behaviors or interests.
  • Mild symptoms of autistic disorders.
  • Perform repetitive actions
  • Have sensory sensitivity
  • Show clumsiness due to under developed motor skills.
  • They often feel heavily isolated from their peers all the way into adulthood.

As per the 5th Edition of DSM-5, Asperger’s Syndrome is very similar to High functioning autism. As such the researchers have removed Asperger’s Syndrome from DSM-5.

Pervasive Developmental Disorders-Not Otherwise Specified (PDD-NOS)

PDD-NOS is a type of autism and commonly referred to as atypical autism. It is considered as one of the milder forms of autism. It exhibits some (but not all) of the autistic characteristics such as social impairment, communication disabilities, and shows stereotype/repetitive behavior. PDD-NOS generally occurs during infancy, but the condition is usually not identified until the child is 3-4 years old.  It meets some (but not all) criteria of Autistic Disorders and Asperger’s Syndrome. But PDD-NOS is more severe than Asperger’s Syndrome and less severe than Autistic Disorder. Individuals with PDD-NOS exhibit some of the following autism features:

  • Problems in speaking and understanding language
  • Problems in socialization and communication.
  • Suffer from learning difficulties.
  • Poor eye contact
  • Prefer loneliness
  • Sometimes, may want to make friends but do not know how to do it.
  • Do not understand facial expression and body language and do not know how to do it.
  • Unable to show or understand any gesture.
  • Faces difficulties in sensory issues like sound, light, touch, etc.
  • Causes stress and anxiety for any changes in the daily routine, activity or living environment.

Autistic Disorders

This is also called classic autistic disorders. This type of autism is typically low functioning autism. Autistic disorder is severe than Asperger’s Syndrome and PDD-NOS. The major characteristics of autism are behavior problems, communication problems, social interaction problems and sensory sensitivity problems. Individuals with autism exhibit following features:

  • Problems in socialization, communication and restricted patterns of behaviors and interests.
  • Presence of abnormal or impaired development that is manifested before the age of 3 years.
  • Extremely poor Social and communication skills.
  • Lack in Motor and language skills
  • Significant language delay
  • Unusual behaviors or interests.

Childhood Disintegrative Disorders (CDD)

Theodor HellerChildhood Disintegrative Disorders (CDD) are also known as Heller’s Syndrome and disintegrative psychosis. CDD was originally described by Austrian educator Theodor Heller in 1908, 35 years before Leo Kanner and Hans Asperger described autism. In this type of autism, children develop normally for two years, then starts losing some of their language, social, and motor skills in the age between 2-4 years. Researchers have not yet found the cause of this type of disorders. Overall, the social, communicative and behavioral features of CDD resemble those of autistic disorder.

The child will function abnormally in the following fields:

  • They are unable to develop peer relationship.
  • They might be capable of talking but unable to start and maintain conversations.
  • They show repetitive/stereotyped behavior such as bobbing head up and down.

Rett’s Syndrome

Andreas RettRett’s Syndrome is a rare genetic postnatal neurological disorder occurs only in the girls. This type of autism spectrum disorder can be diagnosed and confirmed medically. The researchers have confirmed the problem is genetic. The syndrome was first described by Austrian neurologist Andreas Rett in 1966. A girl child generally develops normally up to 6-18 months, then start losing her social and communication skills at the age of 1-4 years and resulting severe mental and physical disability in a long run.

  • The head becomes small (microcephaly) and the brain growth is slower.
  • Suffers from significant language and communication impairment.
  • Repetitive hands movement including wringing, washing, clapping and tapping.
  • Problems deteriorate further with the increase of their age.
  • These children have the breathing problem.
  • Difficulties in eating, chewing and swallowing.
  • Sometimes, loose ability to walk even.

This Rett Syndrome is also excluded from types of autism in the Diagnostic and Statistical Manual (DSM-5) as it is a genetic problem.

Types of Autism and Diagnostic and Statistical Manual (DSM-5)

DSM-5The diagnosis of autism changed with the publication of the latest version of DSM-5 in May 2013. DSM-5 is Diagnostic and Statistical Manual used across the USA and a key text for many health professionals across the world. The key change in the latest manual is that it eliminated all the sub-types of autism listed above by dissolving them into only one type of diagnosis called Autism Spectrum Disorders (ASD).

Autism varies by severity and types and affecting kids. So, as per DSM-5, it is diagnosed now by the severity level of the different types of autism spectrum disorder. DSM-5 mentioned 2 criteria for the diagnosis of autism. These are as follows:

  • Deficit in social communications
  • Patterns of restrictive and repetitive behaviors

Depending on the severity of the symptoms autism is classified as different levels as follow:

  • Level 1 (Requiring Support)
  • Level 2 (Requiring Substantial Support)
  • Level 3 (Requiring Very Substantial Support)

Different severity levels of Autism Spectrum Disorder are given in the following table. The information of the table has been copied from DSM5 Diagnostic Criteria of Autism Spectrum Disorder.

Table: Severity levels for autism spectrum disorder (Information of the table is taken from DSM-5)
Severity levelSocial communicationRestricted, repetitive behaviors
Level 3
“Requiring very
substantial support”

Severe deficits in verbal and nonverbal social communication skills cause severe impairments in functioning, very limited initiation of social interactions, and minimal response to social overtures from others.

For example, a person with few words of intelligible speech who rarely initiates interaction and, when he or she does, makes unusual approaches to meet needs only and responds to only very direct social approaches.

Inflexibility of behavior, extreme difficulty coping with change, or other restricted/repetitive behaviors markedly interfere with functioning in all spheres. Great distress/difficulty changing focus or action.
Level 2
“Requiring substantial

Marked deficits in verbal and nonverbal social
communication skills; social impairments apparent even with supports in place; limited initiation of social interactions; and reduced or abnormal responses to social overtures from others.

For example, a person who speaks simple sentences, whose interaction is limited to narrow special interests, and who has markedly odd nonverbal communication.

Inflexibility of behavior, difficulty coping with change, or other restricted/repetitive behaviors appear frequently enough to be obvious to the casual
observer and interfere with functioning in a variety of contexts. Distress and/or difficulty changing focus or action.
Level 1 “Requiring

Without supports in place, deficits in social communication cause noticeable impairments. Difficulty initiating social interactions, and clear examples of atypical or unsuccessful responses to social overtures of others. May appear to have decreased interest in social interactions.

For example, a person who is able to speak in full sentences and engages in communication but whose to-and-fro conversation with others fails, and whose attempts to make friends are odd and typically unsuccessful.

Inflexibility of behavior causes significant interference with functioning in one or more contexts. Difficulty switching between activities. Problems of organization and planning hamper independence.


There were 5 different types of autism spectrum disorders depending upon its different criteria and the degree of severity. Different types of autism have different types of symptoms but the difference is very narrow. However, these 5 different types of autism were represented in the 4th Edition of DSM-5. From the criteria of autism, it is found that Asperger’s Syndrome is high functioning autism and Autistic Disorders is the low functioning autism.

With the publication of the 5th edition of Diagnostic and Statistical Manual (DSM-5) in May 2013, all types of autism were excluded and now there is only one type of autism that is autism spectrum disorders (ASD). Autism is now diagnosed by its severity as lavel1, level2, and lavel3.

Identification of these different types of autism will help us to understand autism more and help for early intervention and development. of our autistic children.