Asperger’s syndrome and autism are no longer considered separate diagnoses. Since 2013, what was previously called Asperger’s has been folded into a single diagnosis called autism spectrum disorder (ASD). Before that change, the two labels described overlapping patterns of social difficulty and restricted interests, with one key distinction: people diagnosed with Asperger’s had no early language delay, while those diagnosed with autistic disorder typically did. Understanding why these categories were merged, and what replaced them, helps make sense of why both terms still circulate.
How the Two Diagnoses Originally Differed
Under the previous diagnostic manual (DSM-IV, used from 1994 to 2013), Asperger’s disorder and autistic disorder were listed as separate conditions. Both involved difficulties with social interaction and the presence of repetitive behaviors or intense, narrow interests. The dividing line came down to early childhood development.
To receive an Asperger’s diagnosis, a child could not have any clinically significant delay in language. The specific benchmark: single words by age 2, communicative phrases by age 3. There also could not be any significant delay in cognitive development, self-help skills, or curiosity about the environment. In contrast, autistic disorder required evidence of delays or unusual functioning before age 3 in at least one of three areas: social interaction, language used for communication, or imaginative play. Autistic disorder also included a separate category for communication impairments, such as delayed or absent spoken language.
Because of the language and cognitive requirements, people with Asperger’s typically had average or above-average IQ scores. This led to the informal (and somewhat misleading) idea that Asperger’s was simply “mild autism” or “high-functioning autism,” though neither of those was ever an official diagnosis.
Why the Distinction Was Eliminated
The American Psychiatric Association merged Asperger’s into the broader autism spectrum disorder diagnosis in 2013 for several practical and scientific reasons. The most fundamental: researchers could not find reliable evidence that Asperger’s and high-functioning autism were actually different conditions. There was no evidence of a distinct cause, no difference in response to treatment, and no meaningful difference in long-term outcomes. Studies showed that individuals who met early language milestones had the same outcomes in adolescence and adulthood as those with significant early language delays, when both groups were matched for IQ.
The old criteria were also proving unworkable in practice. Parents often couldn’t reliably recall whether their child had spoken single words before age 2, which was a core requirement for distinguishing Asperger’s from autistic disorder. A study of more than 300 diagnoses from over 400 clinicians found that nearly half the young people receiving an Asperger’s or related label actually met the DSM-IV criteria for autistic disorder. Perhaps most telling, research showed that the best predictor of whether someone received an Asperger’s diagnosis versus an autism diagnosis was which clinic they visited, not any characteristic of the person themselves.
As the team behind the change put it, the goal was to “clean up a currently hard-to-implement and contradictory diagnostic schema” and to recognize the widespread scientific consensus that Asperger’s is part of the autism spectrum.
What Replaced the Old Categories
The current system uses a single diagnosis of autism spectrum disorder, defined by two core areas: persistent difficulties with social communication and interaction, and restricted or repetitive patterns of behavior or interests. Both must be present for a diagnosis, and the social difficulties must show up across multiple settings, not just at school or just at home.
Instead of subcategories like Asperger’s or autistic disorder, the DSM-5 uses a system of support levels. Each person is assigned a level in both of the two core areas:
- Level 1: Requiring support. This is closest to what was previously called Asperger’s. The person can function with some assistance but struggles with social situations, flexibility, or organization.
- Level 2: Requiring substantial support. More noticeable difficulties in social communication and more rigid or repetitive behaviors that interfere with daily functioning.
- Level 3: Requiring very substantial support. Significant challenges in communication (sometimes minimal spoken language) and behaviors that substantially limit independence.
The system also allows clinicians to note additional details, called specifiers, such as whether the person has accompanying intellectual impairment, language impairment, or another medical or genetic condition. This approach captures far more individual variation than the old subcategories ever could.
What Happened to People Already Diagnosed
The DSM-5 explicitly states that anyone with an established diagnosis of Asperger’s disorder, autistic disorder, or the related category PDD-NOS should be given the diagnosis of autism spectrum disorder. In practice, though, the transition wasn’t seamless. Research found that applying the new criteria resulted in roughly a one-third reduction in overall ASD diagnoses, with the drop as steep as two-thirds for milder presentations. This raised concerns that some people previously diagnosed with Asperger’s might not meet the updated threshold.
The age-of-onset criteria also shifted. The old system required observable signs before age 3. The current criteria say symptoms must be present in the “early developmental period” but acknowledge they may not become fully apparent until social demands exceed a person’s capacity, or may be masked by coping strategies developed over time. This change was particularly relevant for people who would have previously been identified as having Asperger’s, since their challenges often become most visible in adolescence or adulthood when social expectations grow more complex.
Why People Still Use the Term Asperger’s
Despite the diagnostic change, you’ll still hear “Asperger’s” used regularly. Many adults received that diagnosis before 2013 and find it describes their experience more precisely than the broad umbrella of ASD. For some, it’s a meaningful part of their identity. Others use it as shorthand to communicate that they’re autistic without intellectual disability or significant language challenges, since “autism” still carries assumptions about severity in everyday conversation.
At the same time, there’s been a move away from the term in some communities. In 2018, historical research from Herwig Czech, published in the journal Molecular Autism, and a book by Stanford historian Edith Sheffer documented Hans Asperger’s involvement with the Nazi regime in 1940s Vienna, including connections to a clinic where children with disabilities were killed. These findings gave many people an additional reason to retire the eponym, though opinions within the autistic community remain varied.
What the Distinction Means in Practice
If you or someone you know was diagnosed with Asperger’s, that diagnosis still “counts” as autism spectrum disorder. No new evaluation is needed for the label to carry over. If you’re seeking a diagnosis for the first time, the term you’ll receive is ASD with a specified support level.
The practical differences between someone who would have been called “Asperger’s” and someone labeled “autistic” under the old system were always blurrier than the categories suggested. Both groups share the same core neurology: differences in how they process social information, a tendency toward focused interests, and varying degrees of sensory sensitivity. What varies is the intensity of those traits and how much support is needed to navigate daily life. The current framework tries to capture that variation on a continuum rather than sorting people into boxes that clinicians couldn’t reliably tell apart.