There has been a transformation in the care of people with mental retardation since the late 1960s. One of the most important changes has been the movement towards integration, participation and choice for people with mental retardation, being a facet of larger disability, civil, and human rights movements internationally and within nations. This movement has usually formalised in the activities of charitable or advocacy organisations, or consortia of such groups. These have pursued legal challenges to rights deprivation at the national or local level, engagement with bureaucrats involved in policy development, and participation at all levels of the mental retardation service system.
Advances in a number of fields and disciplines, including genetics, psychopharmacology, developmental neuropsychiatry, psychology, and education have also shown promises for improving the treatment and lives of people with mental retardation. In addition, the provision of more appropriate models of social care has had a substantial impact in improving the quality of life of people with mental retardation in community settings, and enabling staff, carers and families to be more involved and more effective.
People with mental retardation represent a heterogeneous group with a varied range of highly complex needs. The different professions involved in this area have diverse perspectives about people with mental retardation, each giving inconsistent and ambiguous terms and categories. In addition, most cultures use ill-defined and changeable social labels, which are either stigmatising or promoted as non-stigmatising. As a result, it is very difficult to be assured that the groups identified in various nations as having mental retardation are comparable, with some definitions potentially encompassing larger segments of the population than others. As well, different terms are used in different countries. In the United Kingdom the Department of Health replaced the term 'mental handicap' with 'learning disability' in the early 1990s, without taking into consideration the different connotation of the term in the rest of the world. The American Association of Mental Retardation decided in 1993 that the term 'mental retardation' should stay, and re-defined it as a significantly sub-average intellectual functioning existing concurrently with related impaired limitations in two or more of the following areas of skills: communication, health care, home living, social skills, community, self-direction, health and safety, functional, academic leisure and work, manifest before the age of 18. 'Developmental disabilities' is also used, instead of mental retardation, mainly in Australia and Canada. In recent years, the term 'intellectual disability' has been adopted by some international organisations and is gaining ground as an 'international term' for people with mental retardation.