What you have to prove
Medical documentation of qualitative deficits in verbal/nonverbal communication and social interaction AND significantly restricted, repetitive patterns of behavior, interests, or activities, AND marked limitation of two (or extreme of one) Paragraph B areas.
Medical evidence SSA expects
Developmental history, ADOS-2 (Autism Diagnostic Observation Schedule) assessments, IEP or 504 plan records for younger adults, occupational and speech therapy records, and caregiver statements.
Common misconceptions
High-functioning adults on the spectrum who live independently and hold jobs rarely qualify. Applications are strongest when paired with comorbid conditions (intellectual disability, epilepsy, severe anxiety).