The 4 types of autism and their characteristics

How are autism spectrum disorders (ASD) classified?

The autism spectrum disorders (ASD) are a group of developmental disorders with symptoms that are usually chronic and can range from mild to severe.. 1 in 100 children may appear to have some form of ASD, although recent research in the United States states that ASD has a prevalence of 68%.

In general, ASD is characterized by impairment in the individual's ability to communicate and engage in social relationships.. It is a complex disorder that affects the development of the individual who suffers from it and is usually diagnosed around the age of 3 years.

There are different types of autism spectrum disorder. However, this classification has undergone some modification with the publication of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V). Below we will review the different subtypes of ASD and the changes reflected in the DSM-V in its latest editions.

Changes in the DSM-V regarding Autism Spectrum Disorder (ASD)

In its fifth edition, the DSM, published by the American Psychiatric Associationhas incorporated changes regarding ASD by eliminating diagnostic criteria used for decades. In fact, over the years, ASD has undergone several modifications in this manual. In its first edition (1952), it was classified under the term "infantile schizophrenia", which is far from the current concept. Each of these changes has created some controversy, and the new edition of the DSM has been no exception..

One of the most notable modifications with respect to DSM-IV refers to the symptomatology of ASD. If in the fourth edition the diagnostic definition of autism spectrum disorder was characterized by three symptoms known as the triad: deficits in social reciprocity, deficits in language or communication and restricted and repetitive repertoire of interests and activities. In the fifth edition there are only two categories of symptoms: deficits in social communication (i.e., it includes the first two previous categories although it presents some changes with respect to these) and restricted and repetitive behaviors.

Moreover, if in the DSM-IV autism belonged to the "pervasive developmental disorders" (PDD). In the DSM-V, this definition has been replaced by "autism spectrum disorders" (ASD), which is included under "neurodevelopmental disorders".

On the other hand, the subcategories of this disorder have also undergone modifications. The fourth edition included five subtypes of autism: autistic disorder, Asperger syndrome, childhood disintegrative disorder, pervasive developmental disorder not otherwise specified (PDD not otherwise specified) and Rett syndrome. In the fifth edition, Rett Syndrome has been omitted, leaving only 4 subtypes.

Types of Autism Spectrum Disorder Disorders

But, what are the characteristics of the types of autism? In the following lines we explain it in detail, although it should be noted that all the phenomena described by these differentiated categories, in practice, overlap a lot and share characteristics.

1. Autism or Kanner Syndrome

This is the disorder that most individuals associate with autism spectrum disorder.It is named Kanner Syndrome after Dr. Kranner, a physician who studied and described this condition in the 1930s.

Subjects with autism have a limited emotional connection with others, and seem to be immersed in their own world.and appear to be immersed in their own world. They are more likely to show repetitive behaviors, for example, they may arrange and rearrange the same group of objects back and forth for prolonged periods of time. And they are highly sensitive to external stimuli such as sounds.

That is, they may become stressed or agitated when exposed to specific noises, bright lights or sounds or, on the other hand, they will insist on wearing certain clothes or colors or will want to be located in certain areas of the room for no apparent reason.

• To learn more about the symptoms of autism and some less known aspects, you can read our article: "Autism: 8 things you did not know about this disorder".

2. Asperger syndrome

Asperger's Syndrome is a more complicated autism spectrum disorder to diagnose and, sometimes, this diagnosis is made later than in the previous case. and, sometimes, this diagnosis is usually made later than in the previous case. This occurs because these subjects with Asperger's have a medium (high) intelligence that can cause the difficulties and limitations that these subjects present to be underestimated.

The deficit is, therefore, in the field of social skills and behavior, being important enough to seriously compromise their development and social and occupational integration. In addition, people with Asperger's Syndrome show deficiencies in empathy, poor psychomotor coordination, do not understand ironies or the double meaning of language and are obsessed with certain subjects.

The cause of Asperger's Syndrome seems to be the dysfunction of several brain circuits.The affected areas are the amygdala, the frontostriatal and temporal circuits and the cerebellum, areas of the brain that are involved in the development of social relationships.

Although the media have helped to spread an image of Asperger syndrome in which this condition is described as a mental disorder associated with high intelligence, it should be noted that most people grouped in this category do not score significantly above the normal IQ, and a very small number of them get very high scores.

• You can learn more about this disorder in our article: "Asperger's Syndrome: 10 signs to identify this disorder".

3. Childhood disintegrative disorder or Heller Syndrome

This disorder, usually referred to as Heller Syndrome, usually appears around the age of 2 years, although it may not be diagnosed until after 2 years of age.although it may not be diagnosed until after the age of 10.

It is similar to the previous ASD because it affects the same areas (language, social function and motor function), although it differs in its regressive and sudden nature. although it differs from them in its regressive and sudden character, which can cause theThis may cause even the subject to become aware of the problem. Individuals with Heller Syndrome can have a normal development up to 2 years of age, and after this time suffer the characteristic symptoms of this disorder. Different studies conclude that this disorder is between 10 and 60 times less frequent than autism. However, its prognosis is worse.

4. Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS)

When the clinical symptoms presented by the subject with autism spectrum disorder are too heterogeneous and do not fit together as a whole. and do not fit in their totality with the three previous types, the diagnostic label "pervasive developmental disorder not otherwise specified" is used.

The subject with this disorder is characterized by a deficit of social reciprocity, severe communication problems and the existence of peculiar, restricted and stereotyped interests and activities.

It should be noted that if the other types of autism are already diverse in themselves, in this last category it is even more important to take into account the unique characteristics of each individual, and not to fall into the trap of letting the label completely explain the person. This classification system is only an aid to help us draw on a number of concepts to better understand this condition, but it does not exhaust all possible explanations of what each person is experiencing and what he or she needs.

Difficulties in the study of autism

Something that must be taken into account about the different types of autism is that is that it is very difficult to study them without falling into biases.. 

For example, it is problematic to investigate the communication patterns of autistic people using their ability to interpret the emotions embodied in the expression of the eyes, since they tend not to focus on that part of the face.

Thus, the inability to interpret these expressions does not exactly mean that they do not know how to interpret the emotions of others, but that they do not know how to do it in that particular way, but perhaps using other ways to do it.

In turn, the errors made by not taking into account these variables that contaminate the studies can lead to the creation of artificial distinctions between types of autism where really only personality variables, motivation when following instructions, etc., are at work.

Bibliographical references:

• Arndt TL, Stodgell CJ, Rodier PM (2005). The teratology of autism. International Journal of Developmental Neuroscience. 23(2-3): 189 - 199.
• Baker, J.P. (2013). Autism at 70--redrawing the boundaries. The New England Journal of Medicine. 369(12): 1089 - 1091.
• Martos, J. et al (Ed) (2005) Autism: The future is today. Madrid: Imserso-APNA.
• Monfort, M and Monfort, I (2001). In the mind 2. A graphic support for training pragmatic skills in children. Entha Ediciones.
• Quill, K.A. (2000). "Do-Watch-Listen-Say. Social and Communication Intervention for children with Autism". Brookes.
• Szatmari, P. (2006) A different mind. A guide for parents. Editorial Paidós.