This is a summary of the different severity levels in ASD, extracted from the American Academy of Pediatrics, Volume 145, Issue 1:

1. Level 1 (“Requiring Support”):
   • Social Affective:
     • Individuals at this level have noticeable impairments in social communication.
     • They may find it challenging to initiate social interactions.
     • Their responses to social cues from others might be atypical or unsuccessful.
     • Some may appear less interested in social interactions.
   • Restricted and Repetitive Behaviors:
     • Inflexibility of behavior significantly interferes with functioning.
     • Difficulties switching between activities are common.
     • Problems with organization and planning impact independence.
2. Level 2 (“Requiring Substantial Support”):
   • Social Affective:
     • Marked deficits in verbal and nonverbal social communication skills.
     • Social impairments persist even with support in place.
     • Limited initiation of social interactions.
     • Reduced or abnormal responses to social cues from others.
   • Restricted and Repetitive Behaviors:
     • Inflexibility of behavior and difficulty coping with change.
     • Other restricted and repetitive behaviors are noticeable.
     • These behaviors interfere with functioning across various contexts.
3. Level 3 (“Requiring Very Substantial Support”):
   • Social Affective:
     • Severe deficits in verbal and nonverbal social communication skills.
     • Very limited initiation of social interactions.
     • Minimal response to social cues from others.
   • Restricted and Repetitive Behaviors:
     • Inflexibility of behavior markedly interferes with functioning in all areas.
     • Extreme difficulty coping with change.
     • Other restricted and repetitive behaviors cause distress and impact focus.