Asperger’s syndrome has historically been considered a form of high functioning autism, and today the two terms are essentially interchangeable in casual use. Neither is an official medical diagnosis anymore. In 2013, both were folded into a single category called autism spectrum disorder (ASD), which replaced several older labels with one diagnosis that accounts for a wide range of traits and support needs.
How Asperger’s and High Functioning Autism Overlapped
Before 2013, the diagnostic manual used by clinicians in the United States listed five separate conditions under “Pervasive Developmental Disorders.” These included autistic disorder, Asperger’s syndrome, and a catch-all category called PDD-NOS (pervasive developmental disorder not otherwise specified). The main thing that distinguished Asperger’s from autistic disorder was language development: a child diagnosed with Asperger’s had no significant delay in learning to talk or in cognitive development, while a child diagnosed with autistic disorder often did.
“High functioning autism” was never a formal diagnosis at all. It was an informal label applied to people who met the criteria for autistic disorder but had average or above-average IQ scores. In practice, the line between Asperger’s and high functioning autism was blurry, and clinicians sometimes used the terms differently depending on their training or preference. Two children with very similar traits could receive different labels depending on which clinician evaluated them.
Why Both Terms Were Retired
The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) merged Asperger’s syndrome, autistic disorder, and PDD-NOS into a single diagnosis: autism spectrum disorder. The World Health Organization followed in 2019, making the same change in its own classification system, the ICD-11. After roughly three decades as a standalone diagnosis, Asperger’s was officially absorbed into the broader autism category worldwide.
The reasoning was partly scientific. Research consistently showed that the boundaries between Asperger’s and other autism diagnoses didn’t hold up well. Clinicians couldn’t reliably distinguish between the conditions, and brain imaging studies found overlapping but inconsistent patterns of structural and functional differences rather than clean dividing lines. The spectrum model better reflected the reality that autistic traits vary continuously in type and intensity rather than falling into neat subcategories.
There was also a historical factor. Hans Asperger, the Austrian pediatrician for whom the syndrome was named, was long regarded as a champion of the children he studied. He was even characterized as a hero who saved autistic children from Nazi persecution by emphasizing their intelligence. Research published in 2018, however, documented that Asperger collaborated in the murder of children with disabilities under the Third Reich. This finding accelerated an already existing shift away from the eponym in many clinical and advocacy communities.
Why “High Functioning” Is Misleading
Even though “high functioning autism” is still widely used in everyday conversation, a growing body of evidence shows the label can obscure more than it reveals. The term typically refers to autistic people with average or high IQ scores, but IQ turns out to be a poor predictor of how well someone manages daily life.
A large study of 2,225 autistic children and adolescents examined the relationship between IQ and adaptive behavior, which includes practical skills like brushing teeth, tying shoes, or navigating public transportation. Autistic children without intellectual disability scored an average of 28 points below their IQ on measures of daily functioning. By comparison, autistic children with intellectual disability scored only 4.5 points below their IQ on the same measures. In other words, the gap between cognitive ability and real-world functioning was dramatically larger in the group most people would call “high functioning.”
As lead researcher Andrew Whitehouse put it, the term “completely disregards the difficulties these individuals have on a day-to-day basis.” Someone who excels academically may still struggle significantly with sensory overload, executive functioning, social exhaustion, or self-care. The label can also have concrete consequences: policymakers and insurers have used “high functioning” as a reason to deny services or funding, rather than evaluating what an individual actually needs.
How Autism Is Diagnosed Now
Under the current system, an ASD diagnosis requires two things. First, a person must show persistent differences in social communication and social interaction, such as difficulty reading facial expressions, challenges with back-and-forth conversation, or trouble developing and maintaining relationships. Second, they must show at least two types of restricted or repetitive behaviors, interests, or activities. These could include intense focus on specific topics, strong preferences for routines, sensory sensitivities, or repetitive movements.
Importantly, the DSM-5 allows clinicians to diagnose based on both current and past functioning. This means someone whose traits weren’t obvious in early childhood but became apparent in adolescence or adulthood can still receive a diagnosis. This change has been especially significant for adults, women, and people of color who were historically underdiagnosed.
Rather than sorting people into subcategories like Asperger’s or autistic disorder, the current system assigns a level of support need in two areas: social communication and restricted/repetitive behaviors. Level 1 means “requiring support,” Level 2 means “requiring substantial support,” and Level 3 means “requiring very substantial support.” A person who would have previously been diagnosed with Asperger’s would most often fall into Level 1. For example, someone at Level 1 for social communication might need prompting to ask for help and coaching to interpret nonverbal cues, but can carry on conversations and function independently in many settings.
What Happened to Existing Diagnoses
If you or someone you know received an Asperger’s diagnosis before 2013, that diagnosis wasn’t erased. Previous diagnoses of Asperger’s and PDD-NOS were grandfathered into the new ASD category. No one needs to be reevaluated under the updated criteria to keep their diagnosis, and states that adopted the DSM-5 standards generally consider former Asperger’s diagnoses to qualify under their autism service categories.
That said, access to services can vary depending on where you live. State rules around education programs and insurance coverage for autism-related supports differ, and the practical impact of the diagnostic change has been uneven. If you’re navigating services, it’s worth checking your state’s specific policies on ASD coverage.
Why Many People Still Use the Term
Despite the official changes, “Asperger’s” remains common in everyday language. Some autistic adults who grew up with the diagnosis feel a strong connection to the term as part of their identity. For others, it provides a shorthand that quickly communicates a specific profile of traits, particularly in social situations where explaining the full spectrum framework would be impractical.
At the same time, many in the autistic community have moved away from both “Asperger’s” and “high functioning,” viewing them as labels that create an unhelpful hierarchy. The concern is that calling someone “high functioning” minimizes their struggles, while calling someone “low functioning” minimizes their strengths. The spectrum model, while imperfect, at least acknowledges that a person’s support needs can vary across different areas of life and can change over time.
For adults exploring whether they might be autistic, screening tools like the RAADS-R (Ritvo Autism Asperger Diagnostic Scale-Revised) are designed to pick up autistic traits even in people who have learned to mask or camouflage them over the years. A score above 65 suggests some autistic traits are present, while scores above 106 indicate a strong pattern. These tools aren’t diagnostic on their own, but they can be a useful starting point before seeking a formal evaluation.