What is Autism Spectrum Disorder (ASD)?
A comprehensive guide on the definition, symptoms, DSM-5 and ICD-11 criteria, sub-types, and support levels of Autism Spectrum Disorder (ASD).
What is Autism Spectrum Disorder?
Autism Spectrum Disorder (ASD) is an inborn neurodevelopmental difference that shapes how the brain develops and operates. Autistic individuals perceive, experience, and communicate with the world differently than neurotypical individuals.
> [!TIP]
> Viewing autism as natural human neurodiversity rather than a "defect" or "disease" fosters an environment where autistic individuals can thrive.
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Why "Spectrum"? Support Levels Explained
Autism is termed a **spectrum** because traits and support needs vary significantly from person to person. Former sub-categories like Asperger's Syndrome, PDD-NOS, or Kanner's Syndrome are no longer diagnosed separately in current medical manuals (DSM-5); they exist under the unified umbrella of **Autism Spectrum Disorder**.
Instead of sub-type labels, individuals are evaluated by their required support levels:
Level 1 (Requiring Support): Formerly known as Asperger's profile. Individuals communicate fluently, but face challenges in unwritten social cues or cognitive flexibility.
Level 2 (Requiring Substantial Support): Marked differences in verbal and non-verbal communication. Daily routines are essential, and changes cause significant distress.
Level 3 (Requiring Very Substantial Support): Severe differences in communication; spoken language may be limited. Requires ongoing daily living support.
| Former Term | Current DSM-5 / ICD-11 Equivalent |
|---|---|
| Asperger's Syndrome | Autism Spectrum (Level 1) |
| PDD-NOS / Atypical Autism | Autism Spectrum (Variable Level) |
| Classic/Kanner Autism | Autism Spectrum (Level 2-3) |
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Core Characteristics and Diagnosis
Diagnosis relies on clinical observation across two core domains:
1. **Social Communication & Interaction:** Differences in eye contact, reciprocal conversation, interpreting non-literal language (sarcasm/idioms).
2. **Repetitive Behaviors & Sensory Traits:** Repetitive motor movements (stimming like hand flapping or rocking), insistence on sameness/routines, intense special interests, and sensory hyper- or hypo-reactivity.