When behavior is the only language left.

An NCSA family resource for sharing with your clinical team.

Severe behavior change in autism rarely points to “just autism.” For people with severe forms of autism and intellectual disability, sudden behavior change often signals something medical, neurological, or psychiatric that words cannot name. When clinicians attribute it to autism, the real cause stays hidden. Researchers call this diagnostic overshadowing.

This one-page resource is built for families to print and bring to appointments. It walks through the workup algorithm, introduces a 60-second screen for catatonia, and links to five peer-reviewed studies for clinicians.

The behavior is the symptom. The cause is often elsewhere.

Diagnostic overshadowing infographic: workup algorithm and Catatonia Quick Screen

Full articles for clinicians

See also: Clinician Training on Catatonia in Autism (Project ECHO, 2026)