Disclaimer: Any information provided in this article is not meant to diagnose or treat. It should not replace the consultation with a professional qualified to deal with the autistic spectrum disorder (ASD).
The Autistic Spectrum Disorder (ASD) is a genetic condition that afflicts 1 in 59 newborns (US statistics). The disorder is characterized by some typical symptoms with changing intensity and combinations.
Until 2013, DSM-4 identified 5 types of autism; however, in 2013 the American Psychiatric Association revised such nomenclature, introducing the term “autism spectrum disorder” to give physicians, caregivers, and families a clearer taxonomy.
It is appropriate to review both the older and the newer classifications, as many individuals are still diagnosed according to DSM-4. The DSM-5, in place since 2013, is now the new standard that is applied to all new diagnoses.
DSM-4 classification (valid until 2013)
Until 2013 people with autism were classified into five types (from moderate autism, or high functioning autism, to more severe forms, called low functioning autism).
As a matter of fact, the DSM-4 classification was somehow confusing, and therapists could understand the meaning of each type in a different way (leading to unstandardized diagnosis). For these reasons, the American Psychiatric Association updated DSM-4 in 2013.
1) Pervasive Developmental Disorder (PDD-NOS)
PDD autism was called “atypical autism” and was characterized by the presence of milder or fewer symptoms compared to those of Asperger’s and “Classic” autistic persons.
Somehow, atypical autistic people met the criteria of the other two types but did not fall in either one clearly. PDD autism is now close to what DSM-5 calls “social communication disorder”.
2) The Asperger’s Syndrome (high-functioning autism)
Briefly said, Asperger’s Syndrome was considered the second mildest type of autism. In this category were classified highly functional individuals with mild impairment of their social skills and a tendency to have a narrow range of interests.
People with Asperger’s syndrome by DSM-4 are now classified as Level 1 ASD, according to DSM-5.
3) Autistic Disorder (“Classic” Autism)
This was the classic type of autism, characterized by the simultaneous presence of remarkable language and intellectual delays, social and communication deficiencies, and unusual behaviors and interests.
This type, the most severe on the scale, was the most commonly diagnosed if compared to the other 2 different types of autism.
4) Childhood Disintegrative Syndrome (Heller’s Syndrome)
The Childhood disintegrative disorder also called disintegrative psychosis or “Heller’s syndrome”, is an uncommon condition characterized by normal development of the child until 2 to 10 years of age, followed by a severe, unexpected and rather quick deterioration of her/his social, communication and sensory skills.
The root cause of CDD has not been found yet (seems neurological); CDD is one of the most devastating experiences the affected families, and the children themselves (unfortunately, most of them are able to realize the progressive deterioration of their skills).
5) The Rett Syndrome
The Rett syndrome is a genetic disorder that can be medically diagnosed and that affects girls mostly (if not exclusively). Before DSM-5, the Rett Syndrome was considered a type of autism; since 2013, and the introduction of DSM-5, it is no longer considered on the autism spectrum.
Girls affected by the Rett syndrome are characterized by a mild level of social impairment, and by the inability to use their hands properly.
DSM-5 classification (valid starting from 2013)
In 2013, the American Psychiatric Association released the fifth edition of its Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to make the classification of the different types of autism clearer for anyone involved, from parents to therapists, and decrease the level of uncertainty and the lack of standardization existing in the previous classification DSM-4.
The DSM-5 nomenclature is the standard reference that healthcare providers shall use to diagnose a number of mental and behavioral disorders, including autism.
According to DSM-5, autism is now considered a specific pathology (called “autism spectrum disorder”) and is classified in three levels of growing severity depending on an increasing level of support required by the affected individual:
- Level 1 (“Support Required”)
- Level 2 (“Substantial Support Required”)
- Level 3 (“Very Substantial Support Required”)
Level 1 Autism type (high functioning autism)
This is the case of those people that have deficits in social communication that may cause significant and evident impairment in case of lack of support.
People with level 1 autism, experience challenges with social interactions, struggle to create new relationships and respond in unconventional manners to social challenges (that others may perceive as awkward). Cognitive and language abilities may not be impaired, but interactions with others are somehow odd and typically unsuccessful.
A higher level of inflexibility and strict behavior are also generally present, which interfere with the possibility to interact in a flexible way in multiple contexts. Isolation and solitude are the general outcomes of this condition, in case of lack of support.
This is the closest type to the Asperger’s Syndrome pre-2013.
Level 2 Autism type (classic autism)
This is the closest case to the older “classic autism”: the person shows evident challenges with verbal/non-verbal communication, social interaction (even when support is available), awkward response to social challenges, and a rather narrow span of interests.
Level 2 autistic persons are also characterized by inflexible behavior and rules, resistance to change, repetitive movements and patterns that limit the possibility of the individual to operate efficiently in most contexts (sometimes even at home). Any change in routine is perceived with great distress and anxiety.
People with level 2 autism require substantial aid from parents, tutors, caregivers and special education routes and they have a lower-than-average functionality.
Level 3 Autism type (low functioning autism)
Level 3 autism is the most severe type: the individual has clear impairments at all levels (social interactions, communication, language, learning). Social activity is very limited, speech is basic and most times difficult to understand, and isolation is the most natural attitude.
Level 3 autistic persons require very substantial support on a daily basis to survive. Low functioning autism is a very pervasive condition both for the individual, the families, and the caregivers.
Why the different types of autism have been revised by DSM-5?
There are basically three reasons that explain why the American Psychiatric organization revised DSM to get a more accurate definition, classification and treatment options for mental health disorders:
- To allow specialists to formulate a more accurate diagnosis
- To identify the conditions that entitle the patient to special treatment and support
- To help the assessor define the severity level of the disorder
- To have a consistent diagnosis that enables relevant statistical analysis about autism
The differences between the older and the latest autism types classification (DSM 4 vs. DSM 5) can be summarized as follows:
- Consolidates the three pre-existing ASD symptoms (impairment of social, communication and behavioral skills) into just two categories (restricted behavioral patterns, including sensory deficiencies, and persistent challenges in social communication skill)
- Instead of having three different categories (PDD-NOS, Asperger and Autism Disorder), DSM-5 identifies autism as a unique disorder (called ASD, autism spectrum disorder) with three levels of intensity (from mild to severe) in terms of required support by parents and therapists (low, high, very high)
- Introduction of three explicit severity levels (autism scale: 1,2, and 3)
- Introduction of additional assessment areas in the diagnosis: genetic tests (Rett and fragile X syndrome), intellectual ability, speech impairment, and analysis of medical symptoms (gastrointestinal issues, anxiety, sleep disorders)
- Introduction of the new category of social communication disorder (a type similar to the PDD type of DSM-4) which is now not considered an ASD type but a communication disorder only. As this new type of pathology doesn’t fall into the autism spectrum disorder, families may struggle to get access to specific support plans funded by the state.
Should older patients (assessed with DSM 4) be re-assessed with DSM-5?
The American Psychiatric organization suggests parents have their children re-assessed with the new nomenclature, therefore the answer is yes. This may be important also to get access to state-sponsored support and therapies.