Introduction
If you're trying to understand the difference between high-functioning autism and Asperger's syndrome, here's the most important thing to know first: both terms are contested, both have been moved away from in current formal practice, and the question "what's the difference" doesn't have the clean clinical answer the question implies. This piece engages with what each term meant historically, why the current language has shifted, and what the current diagnostic reality actually looks like.
The Short Version
Both "high-functioning autism" (HFA) and "Asperger's syndrome" are informal terms that don't appear as separate diagnoses in current major diagnostic systems. The DSM-5 (American Psychiatric Association, 2013) and the ICD-11 (World Health Organization, in effect since 2022) both fold these earlier categories into autism spectrum disorder (ASD) with specified support level (Level 1, 2, or 3).
The historical distinctions sometimes drawn between the two terms:
- Asperger's syndrome required no significant language delay during early development, and average or above-average IQ
- High-functioning autism could include some early language delay that resolved, also typically with average or above-average IQ
- In practice, the two terms were often used interchangeably even before 2013
But these technical differences are largely artifacts of pre-2013 diagnostic categories. Both terms now refer informally to similar populations, autistic individuals who use spoken language, have average or above-average IQ, and present with what was traditionally considered "milder" support needs. And both terms carry significant baggage that's worth understanding.
Why "Asperger's Syndrome" Carries More Than a Diagnostic History
This is the part most articles on this topic skip, and it matters. The term "Asperger's syndrome" comes from Hans Asperger, an Austrian pediatrician whose work in the 1940s described what he called "autistic psychopathy" in children. He's been credited as a founding figure in autism research.
But research published since 2018, particularly by historian Herwig Czech (in Molecular Autism, 2018), documented something else: Hans Asperger actively cooperated with the Nazi regime during his work in Vienna.
The documentation includes:
- His referrals of children he deemed "unsalvageable" to the Am Spiegelgrund clinic in Vienna, where many were killed as part of the Nazi euthanasia program (the "T4" program and its successors)
- His participation in eugenics frameworks that sorted children by their potential value to the regime
- His complicity in a system that murdered disabled children
This history has led many autistic adults, including many previously diagnosed with Asperger's syndrome, to move away from using the term. Many autistic advocacy organizations have similarly distanced themselves from the term.
At the same time, some autistic adults who were diagnosed with Asperger's syndrome before 2013 continue to identify with the term. They built community, identity, and language around it for years. Their continued identification is meaningful, and it's their right to use what fits them. This piece isn't asking anyone to abandon the language they identify with. It's providing context that's relevant to deciding whether to adopt the term as a new language.
Why "High-Functioning Autism" Is Also Contested
The HFA terminology has its own significant problems, separate from Asperger's history.
The autistic community has been increasingly clear about why:
It collapses distinct dimensions. "High-functioning" gets used as if it means the same thing as "high IQ", but IQ, functional ability, support needs, and masking are genuinely different things that don't move together. An autistic person can have high IQ and significant support needs, or average IQ and high functional independence in specific contexts.
It hides support needs. People described as "high-functioning" are often assumed not to need support, when in fact many have substantial executive function, sensory, social, and mental health support needs that aren't obvious. The label can lead to inadequate accommodations.
It privileges masking. The "high-functioning" label often correlates with the person's ability to mask autistic traits in public. Sustained masking has documented mental health costs (anxiety, depression, autistic burnout), and labels that reward it are part of the problem.
It sorts autistic people into a hierarchy. Implicit in HFA/LFA labeling is the assumption that some autistic people are higher-functioning than others, which determines cognitive performance and visible independence.
For a fuller exploration of why this term is contested, see our hub piece on what "high-functioning autism" means.
What Current Diagnosis Actually Looks Like
Since 2013, the DSM-5 (and now DSM-5-TR) categorizes autism as autism spectrum disorder (ASD) with three specified support levels:
- Level 1 — Requiring support. This is the support level most often applied to people who would previously have been called "high-functioning" or labeled with Asperger's syndrome. The category recognizes that support is needed, even when it's less intensive than at other levels.
- Level 2 — Requiring substantial support. More significant support is needed across social communication and behavioral domains.
- Level 3 — Requiring very substantial support. Significant support across multiple areas of functioning.
The ICD-11 (World Health Organization), which went into effect in 2022, uses a similar single-diagnosis-with-specifiers approach.
What this means practically:
- New diagnoses don't use "Asperger's syndrome" or "high-functioning autism" as formal labels
- A current diagnostic report for someone who would previously have received either label typically says "autism spectrum disorder, Level 1 (requiring support)"
- The Level 1 designation isn't a "milder" version of autism — it just describes the support needs identified at the time of evaluation, which can change across life stages
For more on what evaluation actually looks like, see our piece on how autism diagnosis is done.
Why People Still Use Both Terms
Despite the formal change, both terms still appear in everyday conversation, older medical records, popular culture, and some clinical practice. There are several reasons:
Identity built over decades. People diagnosed before 2013, particularly with Asperger's, may have built an identity around the term for years. Asking them to abandon a label that's been meaningful is sometimes more harm than help.
Practical communication. When someone says they have "high-functioning autism" or "Asperger's," other people often have a reasonable approximation of what they mean, even if those labels aren't current diagnostic categories.
Older clinicians. Some clinicians trained before 2013 still use the terms in practice, particularly in informal communication.
Popular culture. Books, films, and media that reference Asperger's syndrome are part of cultural memory. The character of Sheldon Cooper in The Big Bang Theory, references to "Aspies" online, and various other cultural touchpoints keep the term in circulation.
Understanding what people mean when they use either term is practically useful, even when the current formal diagnosis doesn't use them.
What This Means for Families
For families navigating these terms:
If you're seeking a diagnosis now, you'll receive an ASD diagnosis with a support level rather than either historical label. That's the current diagnostic reality regardless of how the diagnosing clinician personally uses language.
If you've been told your child "would have been Asperger's" or "would have been high-functioning autism", that's a clinician translating current diagnostic categories back into older language. What they typically mean is "ASD Level 1, with average-to-above-average cognitive abilities and developed language." The current label is more accurate; the older translation may be more familiar.
If you or a family member was diagnosed before 2013 with either term, that diagnosis remains valid. You don't have to "update" the diagnosis. How you talk about it now is your choice. Many people use current language, some continue with the older terms, and others use both flexibly. There's no required answer.
If you're encountering these terms in media or older records, both still refer to broadly similar autistic populations, verbal, average-to-above-average IQ, and what was historically considered "milder" support needs. The differences between them are mostly artifacts of pre-2013 categorization.
If you're trying to communicate about an autistic child or family member, the current best practice is to describe their specific support needs in specific contexts rather than relying on labels. "He uses a communication device for social situations and needs sensory accommodations at school" is more useful than any label.
What About Treatment Implications?
A clarification: there's no specific treatment that's distinct for "HFA" versus "Asperger's" versus other ASD presentations. All of these populations may benefit from various supports, speech-language pathology when communication differences are present, occupational therapy for sensory and executive function support, mental health support (anxiety and depression are notably elevated in this population, often related to masking pressure), academic accommodations, and ABA for specific goals when individualized appropriately.
Treatment is determined by the specific person's needs, not by which historical label was applied. For more on evaluating ABA specifically, including questions to ask any provider, see our pieces on whether ABA is ethical and recognizing red flags in ABA therapy.
Conclusion
The most useful framing on this topic is moving from "what's the technical difference between these two labels" to "what does this specific autistic person need." Labels are tools that sometimes help and sometimes obscure; the person themselves is the actual subject.
At Steady Strides ABA, we work with autistic children across Texas, and our approach centers on individual support needs rather than on category labels that may or may not match how a given child presents.
If you'd like to talk through what kind of support might fit your specific family member, contact us for a conversation with a BCBA.
Frequently Asked Questions
Are high-functioning autism and Asperger's the same thing?
In current clinical practice, neither is a formal diagnostic category. Both have been folded into autism spectrum disorder (ASD) with specified support levels in the DSM-5 (since 2013) and ICD-11 (since 2022). Historically, they were sometimes treated as distinct (Asperger's required no early language delay; HFA could include resolved language delay), but in practice, the terms were often used interchangeably even before 2013. For practical purposes today, when someone uses either term, they're typically describing similar populations: verbal, average-to-above-average IQ, what was traditionally considered "milder" support needs.
Why is "Asperger's" sometimes considered a problematic term?
Two reasons. First, like all formerly-separate autism categories, Asperger's syndrome is no longer a current diagnostic label. It's been folded into ASD. Second, and more significant: research published since 2018, particularly by historian Herwig Czech, documented that Hans Asperger (the Austrian pediatrician the term is named after) actively cooperated with the Nazi regime in Vienna, including referring children he deemed "unsalvageable" to a clinic where many were killed as part of the Nazi euthanasia program. This history has led many autistic adults and advocacy organizations to move away from the term. At the same time, some autistic adults diagnosed before 2013 continue to identify with the term, and their identification is meaningful.
What's the current diagnostic category for what used to be called Asperger's?
Autism spectrum disorder (ASD), Level 1, requiring support. The DSM-5 specifies three support levels (Level 1, 2, and 3) that replace the previous separate diagnoses of Asperger's syndrome, Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), and Autistic Disorder. Level 1 is the support level that historically would have included most people diagnosed with Asperger's. ICD-11 uses a similar single-diagnosis-with-specifiers approach.
If I were diagnosed with Asperger's before 2013, am I still "autistic" now?
Yes. The diagnostic category changed in 2013, but your underlying diagnosis remained valid. You don't have to "update" the label. Many people in your situation describe themselves as autistic now (using the broader current term), some continue to identify with Asperger's, and others use both flexibly depending on context. There's no required answer. What fits you is your choice. The autistic community is broad enough to include people with various relationships to these labels.
What's the practical difference between HFA and Asperger's in terms of support needs?
In practice, very little. Both terms historically described populations with similar broad characteristics, verbal speech, average-to-above-average IQ, and what was traditionally considered "milder" autism traits. Support needs depend on the specific individual, not on which label was applied. Specific factors that affect support needs include: sensory profile, executive function challenges, mental health (anxiety and depression are common in this population), social communication preferences, and what accommodations are available in the person's environment. Two people with the "same" diagnostic label can have substantially different support needs.
Should I avoid using either term?
For new conversations, current language tends to work better, "autistic person" (identity-first), "autism spectrum disorder Level 1" (clinical), or specific descriptions of support needs and characteristics rather than category labels. But context matters. If you're talking with someone who identifies with "Asperger's," using their preferred language is respectful. If you're reading older medical records or popular culture references, understanding what either term means is useful. The most flexible approach is being fluent in the current language while not invalidating people who use older terms meaningfully.
SOURCES:
https://www.nimh.nih.gov/health/topics/autism-spectrum-disorders-asd
https://my.clevelandclinic.org/health/articles/24291-diagnostic-and-statistical-manual-dsm-5
https://molecularautism.biomedcentral.com/articles/10.1186/s13229-018-0208-6
https://autisticadvocacy.org/about-asan/about-autism/
https://www.healthychildren.org/English/health-issues/conditions/Autism/Pages/default.aspx
https://www.autism.org.uk/advice-and-guidance/what-is-autism/the-history-of-autism
