Over the past several decades, the way autism spectrum disorder (ASD) is understood has developed and changed. As research has expanded, so too has the way clinicians identify and diagnose autism. The Diagnostic and Statistical Manual of Mental Disorders (DSM) is used as a standardised tool to classify and diagnose mental health issues, including ASD. The DSM is used internationally and is the dominant manual that Australian clinicians use for diagnostic criteria. The DSM is continually updated to reflect changes in research and the current understanding of mental conditions. Currently, five editions have been published, each with varied criteria for diagnosing ASD. In this article, we examine how the diagnosis and classification of Autism have evolved in the DSM, why the criteria have been updated, the impact of these changes, and what lies ahead.
A brief history of autism spectrum disorder
Autism has not always been recognised the way it is now. The first two editions of the DSM (DSM-I and DSM-II) did not recognise autism as its own unique category, instead associating the diagnosis with schizophrenia. It was not until the third edition (DSM-III), published in 1980, that autism was separated from schizophrenia and characterised as a “pervasive developmental disorder”. This led to autism being viewed not as an illness or something caused by the way a child was brought up by their mother, which had been suggested as a cause in the 1940’s, but as something that a person was born with, which impacts their development and who they are.
The fourth edition of the DSM (DSM-IV), published in 1994 and revised in 2000, first recognised the spectrum of ASD and introduced five diagnostic categories under the umbrella of “pervasive developmental disorders”. The five categories were autistic disorder, Asperger’s disorder, Rett’s disorder, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified. A positive of this separation was that a diagnosis of Asperger’s was able to be given to a more able individual, rather than the more profound diagnosis of autistic disorder. However, although these labels in the DSM-IV aimed to describe different presentations of people who were on the autism spectrum, many clinicians and researchers found the boundaries between each category unclear.
Why was the criteria updated to the current DSM-5?
As autism research continued, clinicians and researchers identified that the previous diagnostic categories of the DSM-IV did not adequately reflect the complexity, nor the current understanding of ASD. Also, other issues were beginning to emerge, including unreliable diagnosis of atypical presentations, sensory differences not being appropriately recognised, and funding differences existing across the pervasive developmental disorders (which meant clinicians were occasionally swayed to make a specific diagnosis even if it was not the most accurate diagnosis). In an attempt to address some of these issues, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published in 2013 and revised in 2022, made drastic changes.
The shift to autism spectrum disorder in the DSM-5
Controversy surrounded some of the changes in the DSM-5, notably the complete removal of the “pervasive developmental disorders” category, and instead having one umbrella diagnostic category– “autism spectrum disorder”. Instead of the traditional three domains (i.e., impaired social reciprocity, impaired language/communication, and restricted and repetitive patterns of interests/activities), the manual collapsed symptoms into two domains, namely (1) social communication deficits and (2) restricted interests/repetitive behaviours. Finally, to better encapsulate the ranging impact of a diagnosis across those diagnosed with ASD, the DSM-5 included three specifiers on the level of support a person requires. Namely, level 1 was classified as “requiring support”, level 2 as “requiring substantial support”, and level 3 as “requiring very substantial support”.
What impact did these changes have?
Despite the considerable changes from the DSM-IV to the DSM-5, researchers were able to show that a large percentage of people with previous diagnoses still met the DSM-5 ASD criteria or met the new diagnostic category of social communication disorder (SCD), which is also a recognised neurodevelopmental disorder. This new diagnosis (SCD) in the DSM-5 allowed individuals who had difficulties in social communication, but did not display restricted interests or repetitive behaviours, to be officially recognised.
Although these changes brought some positives, access to funding may have been impacted. For example, a diagnosis of SCD is not typically associated with any funding, and higher levels of ASD are typically allocated more funding. Although the DSM-5 did not intend for the levels of ASD to lead to different funding, this separation of severity was used by funding agencies as a tool to allocate funding.
Looking ahead
There continues to be an increase in the number of people given a diagnosis of ASD. This is almost certainly due to several interrelated factors. Firstly, increased awareness of autism has led to more children being picked up and to a greater number of girls and women being diagnosed. There has also been an increase in children being given more than one diagnosis, for example, Down Syndrome and autism, where previously they may only have been diagnosed with Down syndrome. Furthermore, official diagnoses may have increased to allow individuals to access NDIS funding. Finally, the broader diagnostic criteria may have also led to higher rates. So far, none of the research has supported claims made about there being an autism epidemic due to the impact of vaccines or the use of medication in pregnancy.
Final thoughts
Whether a diagnosis was made under earlier DSMs or under the current DSM-5, it does not define the individual; the diagnostic category simply aims to help explain the unique experience of an individual and to direct support to those who need it. Although Asperger’s disorder has been retired from use, some people who received the diagnosis prior to 2013 still use the term and see it as an important part of their identity. Others prefer to refer to themselves as autistic. There is recognition that it is a matter of personal choice what language people use to refer to themselves.
With the growth and development of neurodiversity affirming practices, autism is now viewed as a natural neurological difference, not a deficit to be fixed. The focus is on accepting and supporting an individual’s unique strengths, communication styles, and sensory needs. Alongside this has been the growing recognition of the unique challenges that people with profound autism, and their parents or carers, experience.
There is lots of information about autism available on the internet and social media. If you are just starting off, finding out about autism, we suggest one of these three websites (two Australian and one English) as good sources of clear, unbiased information
https://www.autismawareness.com.au
https://www.aspect.org.au/about-aspect
If you think you or your child may be autistic, the clinicians at Apex Psychology can provide evidence-based assessments and neuro-affirming therapy. We offer services for children and adults with ASD, please get in touch with reception for more information.