Current Medical Terminology for Intellectual Disability
The proper medical terminology is "Intellectual Disability (Intellectual Developmental Disorder)" or ID/IDD, which replaced the outdated term "mental retardation" in 2013 when the American Psychiatric Association published DSM-5. 1
Official Terminology Change
The American Psychiatric Association formally revised the diagnostic term from "mental retardation" to "intellectual disability (intellectual developmental disorder)" in DSM-5 (2013), aligning with the World Health Organization's International Classification of Diseases (ICD-11). 1, 2
This terminology change reflects a fundamental paradigm shift from viewing this as a static condition to recognizing it as a neurodevelopmental disorder that can be enhanced through environmental supports and interventions. 1
Specific Diagnostic Terms by Age and Severity
The current nomenclature includes three distinct diagnostic categories based on clinical presentation:
Intellectual Disability (Intellectual Developmental Disorder) - The primary diagnostic term for individuals with confirmed deficits in both intellectual and adaptive functioning 1
Global Developmental Delay - Used specifically when clinical severity cannot be reliably assessed in early childhood (under age 5 years) 1
Unspecified Intellectual Disability (Intellectual Developmental Disorder) - Applied to children over age 5 when other impairments (such as sensory or motor deficits) make accurate assessment difficult 1
Person-First Language Requirement
Federal law and professional standards mandate "person-first" language, requiring clinicians to use phrases like "a person with intellectual disability" rather than "intellectually disabled person." 1
This linguistic approach emphasizes the individual's humanity before their diagnosis and should be incorporated into all clinical communications and documentation. 1
Historical Context
The terminology evolution reflects changing societal perceptions:
19th century terms ("cretin," "idiot," "imbecile") are now completely unacceptable and were associated with institutionalization and eugenics practices 1
"Mental retardation" was introduced in 1961 by the American Association on Mental Retardation to replace earlier pejorative terms 1
The American Association on Intellectual and Developmental Disabilities began the shift to "intellectual disability" in 1992, emphasizing the disability construct over a fixed deficit model 1
Diagnostic Framework
The DSM-5 criteria focus on four severity levels (mild, moderate, severe, profound) based on adaptive functioning across conceptual, social, and practical domains rather than IQ scores alone. 1, 2 This represents a significant departure from prior IQ-based classification systems and emphasizes real-world functional capacity. 1