The 3 Levels of Autism

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that affects how individuals perceive and communicate in the world. It includes differences in social interaction and restricted or repetitive behaviors—experienced differently by each person.

Historical Types of Autism (Pre-DSM‑5)

Before the DSM‑5 (2013), autism included several distinct diagnoses:

• Classic autism (Autistic Disorder): Marked by significant social and communication deficits and repetitive behaviors.

• PDD‑NOS (Pervasive Developmental Disorder‑Not Otherwise Specified): Variable symptoms, often milder, but still impacting communication and flexibility.

• Asperger’s Syndrome: Average or above-average language and cognition, with social communication challenges and restricted interests.

• Childhood Disintegrative Disorder (CDD): Rare; loss of previously acquired skills after initial typical development.

These categories are now unified into a single ASD diagnosis to better reflect individual variability.

Current Framework: DSM‑5 Levels of ASD

Today, autism is defined by three levels based on the support needed. It is NOT based on functioning, ability, or intelligence:

Level 1: Requiring Support

• Social communication difficulties (e.g., trouble initiating conversation or interpreting nonverbal cues).

• Rigid routines, difficulty with transitions, and organizational challenges.

• Typically able to manage personal care independently but benefit from coaching or structure.

Level 2: Requiring Substantial Support

• Noticeable social impairments, even with support.

• More frequent or intense repetitive behaviors or restricted interests.

• Support often needed for self-care and daily functioning; speech may be limited or atypical.

Level 3: Requiring Very Substantial Support

• Severe deficits in verbal and nonverbal communication.

• Extreme fixation on routines and repetitive behaviors.

• High sensory sensitivity, frequent meltdowns, and significant limitations in daily living skills.

• Requires assistance in most environments and activities.

  
  

  

Emerging Research: Four Genetic Subtypes

Recent research by Princeton University and the Simons Foundation has identified four genetically distinct subtypes of ASD, moving beyond the three-level framework. These subtypes vary in behavioral traits, developmental history, and genetic origins:

1. Classic traits with comorbid conditions like anxiety, ADHD or OCD

2. Developmental delays with fewer psychiatric issues

3. Milder autism with fewer additional conditions

4. Severe delays tied to new, non-inherited genetic mutations

This shift underscores the need for personalized, biology-informed approaches to intervention and support.

Why It Matters

Understanding autism through these lenses helps businesses, clinicians, and families:

• Customize interventions and supports based on realistic support needs

• Recognize that labels like “high‑functioning” are misleading—autistic individuals may need varied support in different contexts, regardless of intelligence or language ability

• Advocate for early diagnosis and intervention, which can reduce support needs over time, especially between Levels 3 → 2 → 1, depending on access to services like ABA, speech therapy, and occupational therapy