The term “mental retardation” is a diagnostic term denoting the group of disconnected categories of mental functioning such as “idiot”, “imbecile”, and “moron” derived from early IQ tests, which acquired pejorative connotations in popular discourse. The term “mental retardation” acquired pejorative and shameful connotations over the last few decades due to the use of “retarded” as an insult. This may have contributed to its replacement with euphemisms such as “mentally challenged” or “intellectual disability”. While “developmental disability” may be considered to subsume other disorders (see below), “developmental disability” and “developmental delay” (for people under the age of 18), are generally considered more acceptable terms than “mental retardation”.
In North America mental retardation is subsumed into the broader term developmental disability, which also includes epilepsy, autism, cerebral palsy and other disorders that develop during the developmental period (birth to age 18.) Because service provision is tied to the designation developmental disability, it is used by many parents, direct support professionals, and physicians. In the United States, however, in school-based settings, the more specific term mental retardation is still typically used, and is one of 13 categories of disability under which children may be identified for special education services under Public Law 108-446.
The phrase intellectual disability is increasingly being used as a synonym for people with significantly below-average cognitive ability. These terms are sometimes used as a means of separating general intellectual limitations from specific, limited deficits as well as indicating that it is not an emotional or psychological disability. Intellectual disability may also used to describe the outcome of traumatic brain injury or lead poisoning or dementing conditions such as Alzheimer’s disease. It is not specific to congenital disorders such as Down syndrome.
The American Association on Mental Retardation continued to use the term mental retardation until 2006. In June 2006 its members voted to change the name of the organization to the “American Association on Intellectual and Developmental Disabilities,” rejecting the options to become the AAID or AADD. Part of the rationale for the double name was that many members worked with people with pervasive developmental disorders, most of whom do not have mental retardation.
In the UK, “mental handicap” had become the common medical term, replacing “mental subnormality” in Scotland and “mental deficiency” in England and Wales, until Stephen Dorrell, Secretary of State for Health for the United Kingdom from 1995-7, changed the NHS’s designation to “learning disability.” The new term is not yet widely understood, and is often taken to refer to problems affecting schoolwork (the American usage), which are known in the UK as “learning difficulties.” British social workers may use “learning difficulty” to refer to both people with MR and those with conditions such as dyslexia.
In England and Wales between 1983 and 2008 the Mental Health Act 1983 defined “mental impairment” and “severe mental impairment” as “a state of arrested or incomplete development of mind which includes significant/severe impairment of intelligence and social functioning and is associated with abnormally aggressive or seriously irresponsible conduct on the part of the person concerned.” As behavior was involved, these were not necessarily permanent conditions: they were defined for the purpose of authorizing detention in hospital or guardianship. The term Mental Impairment was removed from the Act in November 2008, but the grounds for detention remained. However, English statute law uses “mental impairment” elsewhere in a less well-defined manner—e.g. to allow exemption from taxes—implying that mental retardation without any behavioral problems is what is meant.
In the UK, it is very important to understand that the verbs ‘retardation’ and ‘retarded’ (along with private usage of ‘retard’) are highly, and completely unacceptable in both professional and personal situations – and it is deemed just as offensive as many other stereotypical pejoratives used in the United States. A BBC poll conducted in the United Kingdom came to the conclusion that ‘retard’ was the most offensive disability-related word. On the reverse side of that, when a a contestant on Celebrity Big Brother live used the phrase “walking like a retard”, despite complaints from the public and the charity Mencap, the communications regulator Ofcom did not uphold the complaint saying “it was not used in an offensive context […] and had been used light-heartedly”. It was however noted that two previous similar complaints from other shows were upheld.