What is the medical term for intellectual disability, previously known as mental retardation?

Intellectual Disability: The Current Medical Term for Mental Retardation

The current medical term for what was previously known as mental retardation is "Intellectual Disability" (ID) or "Intellectual Developmental Disorder" (IDD). 1

Terminology Evolution and Rationale

The shift in terminology reflects significant changes in how society and the medical community conceptualize this condition:

• Historical progression: In the 19th century, pejorative terms like "cretin," "idiot," and "imbecile" were used. In 1961, the American Association on Mental Retardation introduced "mental retardation" to replace these terms. 1

• Modern terminology shift:

  • In 1992, the American Association on Intellectual and Developmental Disabilities (AAIDD) changed "mental retardation" to "intellectual disability" 1
  • In 2013, the American Psychiatric Association's DSM-5 officially revised the diagnostic term to "intellectual disability (intellectual developmental disorder)" 1
  • The World Health Organization's ICD-11 recognizes these as "disorders of neurodevelopment" 1

• Conceptual paradigm shift: The change represents more than just terminology - it reflects a fundamental shift from viewing the condition as static to one that can be enhanced through appropriate supports 1

Current Definition and Classification

Intellectual Disability/Intellectual Developmental Disorder is characterized by:

• Significant limitations in intellectual functioning (reasoning, learning, problem solving)

• Deficits in adaptive skills across multiple domains:

  • Conceptual domain (language, reading, math, reasoning, knowledge, memory)
  • Social domain (empathy, social judgment, communication skills)
  • Practical domain (personal care, money management, organization of tasks) 1, 2

• The condition must originate during the developmental period 1

• DSM-5 focuses on four levels of severity based on adaptive functioning rather than IQ scores alone 1

Alternative Terminology Considerations

Some experts have proposed additional terminology options:

• "Developmental cognitive impairment" has been suggested as a co-existing term 3
• The WHO ICD Working Group has proposed "intellectual developmental disorders," defined as "a group of developmental conditions characterized by significant impairment of cognitive functions, which are associated with limitations of learning, adaptive behaviour and skills" 4

Clinical Implications

• The terminology shift emphasizes that intellectual disability is not a static condition but can be improved with appropriate environmental modifications and supports 1
• Person-first language ("a person with intellectual disability") is now the standard in clinical communication 1
• The focus has moved from simply measuring IQ to assessing adaptive functioning across multiple domains 1, 2

Diagnostic Approach

For children under 5 years where severity cannot be reliably assessed, the term "Global Developmental Delay" is used. For children over 5 years where assessment is difficult due to other impairments, "Unspecified Intellectual Disability" is used. 1

This evolution in terminology reflects broader changes in our understanding of disability as an interaction between individual limitations and environmental demands rather than simply an inherent trait of the person.