Evidence / 2001

Population

People with intellectual disability in studies of diagnostic overshadowing (original literature)

Sample

Narrative review of experimental and clinical literature

Condition

Diagnostic overshadowing — attributing symptoms to an existing diagnosis and missing another

Medication focus

Not a treatment trial

Jurisdiction

International

Last reviewed

1 September 2026

DOI

10.1352/0895-8017(2001)106<0416:DORAR>2.0.CO;2

Plain-language finding

Diagnostic overshadowing describes the tendency to attribute signs and symptoms automatically to an existing diagnosis, making another condition harder to recognise. The original experimental literature concerned intellectual disability. The mechanism — a known label becoming a ceiling on curiosity — is clinically relevant wherever a first diagnosis is treated as a complete model of the person.

Important limitation

The foundational experiments are about intellectual disability, not ADHD or autism specifically. Extending the concept to neurodevelopmental and psychiatric comorbidity is a reasoned clinical application, not a new trial finding. This site labels that extension honestly.

Why we cite this

The named review of diagnostic overshadowing as a mechanism. Cited for the concept, with the original population kept visible.

overshadowing · differential · training

Research demonstrates a statistical relationship. Association is not causation. Timing, dose, confounding and missing data still matter.