Autism is officially one diagnosis, not several. Since 2013, what were once separate conditions have been grouped under a single label: autism spectrum disorder (ASD). But the spectrum is broad, and the ways autism shows up in different people vary enormously. Understanding those differences matters whether you’re exploring a diagnosis for yourself, a child, or someone you care about.
Why “Types” Were Replaced by One Diagnosis
Before 2013, clinicians diagnosed several distinct conditions: autistic disorder, Asperger’s syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS), and childhood disintegrative disorder. Each had its own criteria, and the lines between them were blurry. Two children with very similar traits could receive different diagnoses depending on which clinician they saw.
The American Psychiatric Association consolidated all four into autism spectrum disorder in its 2013 diagnostic manual. The goal was consistency. Instead of debating which label fit, clinicians now diagnose ASD and then describe where a person falls on the spectrum using support levels and detailed notes about their specific strengths and challenges. You’ll still hear people use “Asperger’s” informally, especially those who were diagnosed under the old system, but it’s no longer an official clinical category.
The Three Support Levels
The current diagnostic system rates autism severity across two dimensions: social communication and restricted or repetitive behaviors. Each dimension gets one of three levels.
- Level 1 (“requires support”): People at this level can generally communicate and function independently but struggle with social nuance. They may have difficulty initiating conversations, reading social cues, or switching between tasks. Without support, these challenges can create real friction in relationships, school, or work.
- Level 2 (“requires substantial support”): Social difficulties are more apparent even with support in place. Speech may be limited or atypical, and inflexibility around routines or interests causes noticeable problems in daily life. Transitions between activities or environments tend to be especially hard.
- Level 3 (“requires very substantial support”): People at this level have severe challenges with communication, sometimes using very few words or none at all. Repetitive behaviors and extreme difficulty with change significantly affect functioning across all settings, and daily living requires extensive help.
These levels aren’t permanent labels. A person’s support needs can shift over time with therapy, life changes, or new environments. And the levels don’t capture everything. Someone at Level 1 might still face intense sensory overload or anxiety that profoundly affects their life, even if their social communication looks relatively typical on the surface.
The Former Subtypes You’ll Still Hear About
Even though they’re no longer official diagnoses, the old categories still shape how people talk about autism. Knowing what they meant helps make sense of those conversations.
Asperger’s syndrome described people with average or above-average intelligence and language skills who still had significant difficulty with social interaction and showed intense, narrow interests. Many people diagnosed with Asperger’s before 2013 would today receive an ASD Level 1 diagnosis. Some still identify strongly with the Asperger’s label.
PDD-NOS was a catch-all for people who had some autistic traits but didn’t meet full criteria for autistic disorder or Asperger’s. It was sometimes called “atypical autism.” Under the current system, these individuals would be evaluated for ASD and assigned a support level based on their specific profile.
Childhood disintegrative disorder was rare and described children who developed typically for at least two years before losing previously acquired skills in language, social ability, or motor function. This pattern can still occur and would now be diagnosed as ASD with a note about the regression.
Syndromic Autism and Genetic Conditions
About 20% of children with autism have an identifiable genetic syndrome contributing to their traits. Clinicians sometimes call this “syndromic autism” to distinguish it from cases where no specific genetic cause has been found.
Fragile X syndrome is the most common genetic condition linked to autism. Between 1% and 3% of all autistic individuals have Fragile X, and about one-third of people with Fragile X also meet criteria for ASD. The overlap shows up as eye contact avoidance, language delays, and repetitive behaviors.
Rett syndrome was once classified alongside autism in the diagnostic manual but was removed in 2013. It predominantly affects girls, who develop typically at first and then lose milestones, developing movement difficulties, seizures, and intellectual disability. A child with Rett syndrome can still receive a dual diagnosis if they also meet ASD criteria.
Genetic testing doesn’t change the autism diagnosis itself, but it can explain why certain medical issues show up alongside it and help families anticipate what kind of support might be needed.
How Autism Presents Differently in Girls and Women
Autism has historically been identified and studied primarily in boys, which means the “typical” picture of autism that most people carry in their heads skews male. Girls and women with autism often look different. They tend to have stronger surface-level social skills and may develop strategies early in life to blend in with peers. Researchers call this camouflaging: the effortful performance of non-autistic social behavior, learned over time through careful observation and imitation of others.
This camouflaging partly explains why girls and women are diagnosed later or missed entirely. They may feel intense social pressure to fit in, driven by gender-based expectations around friendliness and social engagement. Some research suggests that cognitive differences between sexes may also give some autistic women an enhanced ability to mask their traits. The cost of sustained camouflaging is significant, though. It’s linked to exhaustion, burnout, anxiety, and depression.
Sensory Differences Across the Spectrum
Most autistic people experience sensory input differently, but the direction of that difference varies. Some are hypersensitive, meaning ordinary levels of sound, light, texture, or smell feel overwhelming. A fluorescent light hum or a clothing tag might be genuinely painful or distracting in a way that’s hard to convey to someone who doesn’t experience it. Others are hyposensitive, needing more sensory input than usual before they register it. They may seem unaware of temperature changes, seek out intense physical sensations, or have a delayed response to pain.
Many autistic people experience both patterns depending on the sense involved. Someone might be highly sensitive to sound but seek out deep pressure or movement. These sensory profiles are one of the reasons two people with the same ASD diagnosis can have very different daily experiences and needs.
Conditions That Commonly Occur Alongside Autism
Autism rarely shows up alone. The rates of co-occurring conditions are striking. Seizure disorders affect 25% to 40% of autistic individuals, compared to 2% to 3% of the general population. Chronic sleep problems affect 50% to 80% of autistic children. Gastrointestinal issues are reported in up to 85% of cases, depending on the study. And as many as 85% of autistic children also have a co-occurring psychiatric condition such as anxiety, ADHD, or depression.
These co-occurring conditions aren’t “types” of autism, but they dramatically shape a person’s experience. An autistic child who sleeps well and has no GI issues faces a very different daily reality than one dealing with chronic pain and sleep deprivation on top of sensory and social challenges.
Demand Avoidance as a Behavioral Profile
Pathological demand avoidance, or PDA, describes a pattern where a person goes to extremes to resist anything they perceive as a demand, even routine tasks they’re perfectly capable of doing. Putting on shoes, sitting at a table, or answering a simple question can trigger intense discomfort if the request feels like it’s coming from someone else rather than from the person’s own motivation.
PDA is not a recognized diagnosis or an official subtype of autism. There’s no empirical evidence yet that it’s a distinct neurological condition. But many parents and clinicians find it a useful way to describe a specific behavioral pattern that standard autism strategies (like visual schedules and structured routines) can sometimes make worse rather than better, since those strategies add more external demands.
Adult Diagnosis and Late Recognition
Many adults are now being identified with autism for the first time, particularly those who developed compensatory strategies that masked their traits during childhood. Current CDC data puts autism prevalence at about 1 in 31 among 8-year-olds, but many adults grew up in an era when only the most visibly affected children were diagnosed.
Screening tools designed for adults, such as the RAADS-R, measure traits across areas like social relatedness, sensory sensitivity, and circumscribed interests on a scale from 0 to 240. A score below 65 is generally not consistent with autism, while scores of 140 or above suggest traits strongly consistent with the condition and warrant a full diagnostic assessment. These tools are starting points, not standalone diagnoses. A comprehensive evaluation still requires clinical expertise and a detailed developmental history, and the gold-standard observation tool used by clinicians, called the ADOS-2, is typically part of that process alongside interviews with the person and, when possible, family members who knew them as a child.
For adults exploring a potential diagnosis, the labels matter less than understanding how your brain works. Whether you would have been called “Asperger’s” under the old system or receive a Level 1 ASD diagnosis today, the practical question is the same: what support helps you function at your best?