The Evolution of autism diagnosis: from Asperger’s Syndrome to Autism Spectrum Disorder

The world of neurodiversity is constantly evolving, and with it, the language we use to describe different neurological functioning. A fundamental change, often discussed in relation to autism, is the shift from the diagnosis of Asperger’s Syndrome to its classification as Autism Spectrum Disorder, Level 1, according to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published in 2013. This is not merely a terminological change, but a profound paradigm shift driven by a dual motivation: one strictly scientific and one of an ethical-historical nature.

Scientific Evolution: Autism as a Continuum

For decades, the understanding of autism was fragmented. Autism (in its more “classic” definition), Asperger’s Syndrome, and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) tended to be considered distinct conditions, each with its own specific diagnostic criteria. This separation, however, often created clinical and diagnostic confusion. The boundaries between these categories were blurred and sometimes arbitrary, making it difficult for clinicians to accurately determine where one diagnosis ended and another began.

The evolution of scientific research has gradually clarified that autism manifests not as a set of discrete categories, but rather as a continuum of characteristics. The differences between what was known as Asperger’s Syndrome and other presentations of autism without intellectual or language disability proved to be more quantitative than qualitative. In other words, “Asperger” individuals did not have symptoms different in nature, but rather a lower intensity or a different combination of the same symptoms observed in other forms of autism, especially regarding language and cognitive abilities. This realization made previous diagnostic boundaries not only arbitrary but also poorly reproducible from one clinician to another.

The Concept of Spectrum in Autism

The adoption of the “spectrum” concept in the DSM-5 was the answer to this need for consistency. Autism Spectrum Disorder (ASD) unifies these different presentations under a single diagnostic “umbrella.” The introduction of required support levels (Level 1, 2, 3) allowed for overcoming fragmentation, offering a more functional and personalized description of the condition.

• Level 1 indicates the need for “support” (what was previously often labeled as Asperger’s Syndrome or high-functioning autism).
• Level 2 indicates the need for “substantial support.”
• Level 3 indicates the need for “very substantial support.”

This approach also aligns perfectly with the growing understanding of neurodiversity, which recognizes variations in neurological functioning as part of normal human diversity, rather than as pathologies to be eliminated. The focus shifts from “what’s missing” to “how it functions differently” and “what supports are needed.”

The Ethico-Historical Revelation: Hans Asperger’s Past

Parallel to this scientific evolution, significant historical discoveries played a decisive and, for many, unexpected role in the change of nomenclature. In-depth research, particularly that conducted by historian Edith Sheffer and medical historian Herwig Czech, brought to light the involvement of Hans Asperger—the Austrian pediatrician after whom the syndrome was named—with the Nazi regime.

For a long time, Asperger was portrayed as a silent hero who, despite working under the Nazi regime, strove to protect autistic children from persecution. However, new documentary evidence has shattered this narrative. In-depth historical research has documented that, although not an official member of the National Socialist German Workers’ Party (NSDAP), Asperger actively collaborated with the eugenics program and with Aktion T4, the horrific child euthanasia program implemented by the Nazis.

Research has revealed that Asperger not only conformed to the regime but actively participated in decisions that led to the deaths of children with disabilities. This included the transfer of severely disabled children, some of whom he himself diagnosed with autism, to clinics where they were systematically killed. His participation in such practices, despite some attempts to protect other children deemed “educable” and “useful” to the Reich, raised serious ethical and moral questions that could no longer be ignored.

Faced with these shocking discoveries, the scientific community and associations of autistic people and their families began to question the appropriateness of continuing to use nomenclature that honored a figure with such a problematic and controversial past. The decision to remove the name “Asperger’s Syndrome” from the DSM-5 was therefore also a conscious choice to avoid continuing to honor a figure involved in such horrific atrocities. It was an act of ethical distancing, aimed at purifying diagnostic language from unacceptable moral associations.

A Change for Better Understanding and Inclusion of Autism

The shift from Asperger’s Syndrome to Autism Spectrum Disorder, Level 1, has been a complex but necessary change. From a scientific perspective, it allowed for embracing a more accurate and coherent understanding of autism as a spectrum. From an ethical perspective, it represented an important act of historical responsibility.

This change in nomenclature has not erased the experiences or identities of those previously diagnosed with Asperger’s Syndrome. On the contrary, it aims to promote greater inclusion, more accurate diagnosis, and more personalized support for all autistic people. Recognizing the vast diversity within the spectrum and the need for language that is respectful and based on the latest scientific and moral evidence paves the way for a path of change towards neuro-inclusivity. It is a step forward towards a future where neurodiversity is fully understood, accepted, and valued.