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Early descriptions
Accepted clinical terms were "imbecility", "feeble-mindedness", and "mental deficiency". -
Segregation and isolation
It was thought that intellectual disabilities were caused by poverty, laziness, crime and promiscuity. As a result, it became a societal norm to isolate those that were deemed intellectually disabled. -
Mental Defectives
Martin Barr published a book called Mental Defectives, which was the first text that supported the idea that there were hereditary factors that played into what causes an intellectual disability -
Forced sterilization
Indiana was the first state to pass a law that authorized forced sterilizations of individuals with an intellectual disability that resided in institutions. -
Eugenics
American psychologist Henry H. Goddard publishes The Kallikak Family, a book advocating for those with disabilities that were believed to be hereditary, such as intellectual disability and learning disabilities, should be limited in their ability to reproduce to rid society of these traits. -
Institutions and further segregation
Institutions across the nation begin to reach capacity with continued admissions of individuals with intellectual disabilities or "feeble-mindedness". -
What's in a name:
The American Association for the Study of the Feeble-Minded (an organization that conducted research on individuals with intellectual disabilities and methods of "dealing" with them, including forced sterilization) changed their name to the American Association on Mental Deficiency. -
Forced sterilization takes off
By 1937, there was over 27,000 reported cases of forced sterilization, as efforts increased during the Great Depression. -
Institution overcrowding
The number of individuals with intellectual disability that were in state-funded institutions reached over 140,000 by 1950. Poor conditions in training schools, such as Maryland's State Training School begin being exposed. The Catholic Worker published a story highlight conditions at this school referring to the 'patients' as 'slaves', stating that many of more than 12,000 patients are capable of fully functioning in society, but are trapped there. -
Advocacy on the rise
The National Association of Parents and Friends of Mentally Retarded Children is formed (now known as the Arc). They become the first group to seek government funding for research of intellectual disabilities and present findings of the dangers of lead paint and infancy, among others. Advocates seek more for individuals with intellectual disabilities than being in an institution. -
Landmark law
President Dwight Eisenhower passes PL 85-926, the first federal legislation of $1 million per year to provide support and funding for universities to establish training in the field of special education. -
Mental deficiency to mental retardation
The American Association on Mental Deficiency's manual uses the term "mental retardation" in place of mental deficiency. The American Association on Mental Deficiency (now the American Association on Intellectual and Developmental Disabilities) is the largest and oldest interdisciplinary organization of professionals that focuses on intellectual and developmental disabilities. -
Institutionalization reaches peak numbers
Despite President John F. Kennedy developing a panel to move the U.S. away from institutionalization of individuals with intellectual disability in 1960, the number of individuals living in state-run institutions reached nearly 200,000 people. -
Landmark court case
Pennsylvania Association for Retarded Children v. Commonwealth of Pennsylvania declares that all children with intellectual disabilities has the right to a public education -
Willowbrook exposed
Geraldo Rivera airs a series of exposes on the Willowbrook institution that highlights the deplorable conditions and overcrowding at the institution that contributes to the spread of diseases, malnourishment, and neglect. -
Education for All Handicapped Children Act
President Gerald Ford signed PL 94-142 (no IDEA) into law, sparked by Rivera's documentaries at Willowbrook. The law provides supports and mandates for all students with disabilities the right to an education at a public school (now known as FAPE). -
Willowbrook closes
Willowbrook closed its doors, 15 years after Geraldo Rivera airs a series of investigative reports. -
The Americans with Disabilities Act
The ADA is passed, which ensures the rights and civil liberties of all citizens with disabilities. The legislation provided guidance and requirements for the treatment and accessibility of public places to those with disabilities. -
Institutions on the decline
The number of individuals residing in state-run institutions drops to below 50,000 nationwide. Progress! -
Reauthorization of IDEA (PL 94-142)
The legislation furthers the requirements of inclusion for students with intellectual disabilities receiving special education services in the classroom and requires their involvement and progression within the general education classroom/curriculum. -
IDEA celebrates 35 years
IDEA is declared by President Obama as a landmark civil rights act. The term "mental retardation" is replaced with "intellectual disability" on all pieces of federal legislation. -
Change in definition in the DSM-5
The DSM-5 officially changes "mental retardation" to "intellectual disability". Additionally, the language used to define the classification is changed to be more closely aligned with that of AAIDD. Severity level is now associated with adaptive functioning, rather than IQ. IQ classification is also now based on approximate scales (65-75), rather than a hard cut-off of 70. This now requires more clinical judgement in diagnosing than in the past.