In its 1959 definition and classification manual, AAIDD first attempted a dual-criterion approach: a definition that mentioned both intellectual functioning and in maturation, learning, and “impairments social adjustment.” In its 1961 manual, AAIDD folded the description into the phrase “impairments” behavior,” a term still used today. The definition was refocused in 1992 to reflect a new way “adaptive of understanding and responding to the condition. AAIDD moved away from a diagnostic process that identified deficits solely on the basis of an IQ score, and began considering social, environmental, and other elements as well. Most crucially, the emphasis shifted from providing programs to people with intellectual disability to designing and delivering support tailored to each individual to help them reach their highest level of functioning. The third element of the definition involves age of onset. Early definitions mentioned “the developmental period.” AAIDD’s 2002 definition clarified that the disability originates "before the age of 18.” It is important to note that the 1992 definition was the first to view intellectual disability as a condition that could be enhanced by provision of supports, rather than as a static, lifelong disability. Since 1992, the Association has worked to further develop and refine this paradigm shift. The approach is more fully fleshed out in the Association’s 11th and most recent manual, Intellectual Disability: Definition, Classification, and Systems of Supports, published in 2010.
In its 1959 definition and classification manual, AAIDD first attempted a dual-criterion approach: a definition that mentioned both intellectual functioning and “impairments in maturation, learning, and social adjustment.” In its 1961 manual, AAIDD folded the “impairments” description into the phrase “adaptive behavior,” a term still used today. The definition was refocused in 1992 to reflect a new way of understanding and responding to the condition. AAIDD moved away from a diagnostic process that identified deficits solely on the basis of an IQ score, and began considering social, environmental, and other elements as well. Most crucially, the emphasis shifted from providing programs to people with intellectual disability to designing and delivering support tailored to each individual to help them reach their highest level of functioning. The third element of the definition involves age of onset. Early definitions mentioned “the developmental period.” AAIDD’s 2002 definition clarified that the disability originates "before the age of 18.” It is important to note that the 1992 definition was the first to view intellectual disability as a condition that could be enhanced by provision of supports, rather than as a static, lifelong disability. Since 1992, the Association has worked to further develop and refine this paradigm shift. The approach is more fully fleshed out in the Association’s 11th and most recent manual, Intellectual Disability: Definition, Classification, and Systems of Supports, published in 2010.
DD%20IDD%20Definitions%20final%202%2019%2015.docx