Intellectual Disability Defined

Intellectual Disability is characterized by “significant limitations both in intellectual functioning and in adaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18.” (Source: The American Association for Intellectual and Developmental Disabilities, 2010).

Intellectual disability is not a mental illness. See DPIC’s page on Mental Illness for more information.

Intellectual disability is now the correct term for describing significant limitations in both intellectual functioning and adaptive behavior. Many court decisions, laws, and other official documents were written using the prior designation of “mental retardation.” The shift to the new terminology was given impetus when the American Association on Mental Retardation (AAMR) changed its name to the American Association on Intellectual and Developmental Disabilities (AAIDD) in 2007. AAIDD has taken the position that the meanings of the two terms are identical: “At the heart of this shift is the understanding that this term covers the same population of individuals who were diagnosed previously with mental retardation in number, kind, level, type, and duration of the disability and the need of people with this disability for individualized services and supports,” Robert Schalock et al., “The Renaming of Mental Retardation: Understanding the Change to the Term Intellectual Disability.”

DPIC will endeavor to use the term “intellectual disability,” while recognizing the use of “mental retardation” in court decisions and other quoted materials.