A specific category of disabled people as viewed from within the medical model of disability. Developmental disability refers to people who are otherwise classified as having mental retardation, autism, epilepsy, cerebral palsy, and related conditions including childhood traumatic brain injury. Students of history can see that these are the categories that once occupied the now-defunct label of feeble-minded. To make matters more confusing, developmental disability is sometimes used synonymously with mental retardation, and sometimes is used in a more general way.
The accepted American legal definition of developmental disability is a condition that begins in childhood, is expected to last forever, and impairs someone in more than a certain number of areas. Here is a typical definition from Delaware's developmental service system:
A severe, chronic disability which is attributable to a mental or physical impairment or combination of mental and physical impairments; is manifested before the person attains age 22; is likely to continue indefinitely; results in substantial functional limitations in three or more of the following areas of major life activity: self-care, receptive and expressive language, learning, mobility, self-direction, capacity of independent living, economic self-sufficiency; and reflects the person's needs for a combination and sequence of special, interdisciplinary, or generic care treatments of services which are of lifelong or extended duration and are individually planned and coordinated.1
This definition actually excludes some people who are otherwise diagnosed with mental retardation. It also fails to account for cultural context: In some cultures, people with certain developmental disabilities have as much of a normal role as anyone else within that culture and are viewed as functioning as independently as anyone. This can happen even if white, middle class American culture would exclude the person by default. Parts of my family belong to such cultures, and the attitude and role of many people with developmental disabilities is very different. This isn't an ivory tower word game. It's the difference between having a job, a spouse, children, and most importantly a sense of belonging in one's own community, and being relegated to the short bus and group homes.
A newer definition of developmental disability is becoming popular among researchers. They use the term neurodevelopmental disability to refer to anything from learning disabilities to attention deficit disorder. Some of these conditions are in the legal category of developmental disability, and some are for various reasons outside it. There are also definitions of developmental disability that cover any lifelong condition starting in childhood.
Idiot, retard, moron, imbecile, cretin, and other pejorative and derogatory terms have also been used as medical terms for people with developmental disabilities. Some of them started out as medical terms, but others were insults even before doctors got hold of them. It seems that to some people the biggest insult possible is to be compared to people who learn slower than other people. One of the biggest stereotypes of people with developmental disabilities is that we, or some of us, are children forever, have no sexuality, and are not truly adults even when we are of age. This is far from the truth, but leads to many adults being denied the right to marry, have children, or even have friends who haven't been approved by their guardian. Many have also experienced incarceration and forced eugenic sterilization.
People with developmental disabilities have formed a self-advocacy and human rights movement that usually takes the form of advocacy groups such as People First. There is also, through the joys of balkanization, a separate self-advocacy movement for autistic people and a neurodiversity movement, both of which show an unfortunate tendency to separate themselves from people diagnosed with mental retardation.
The self-advocacy movement has enabled many people to learn our rights and fight for a say in what happens to us. Some such groups have even been the driving force in the closure of institutions2, in large contrast to the stereotype of developmentally disabled people as the village idiot. As one of the most devalued groups of people in the world, people with developmental disabilities unfortunately have a lot of injustice to fight.
1 Delaware Healthcare Association. "Glossary of Health Care Terms and Acronyms". Delaware Healthcare Association. http://www.deha.org/Glossary/GlossaryD.htm. Accessed March 17, 2005.
2 Byzek, Josie and Gwin, Lucy. "People First Win Freedom in Tennessee". Gwin, Lucy, ed. Mouth Magazine. http://www.mouthmag.com/peoplefirst.htm. Accessed March 17, 2005.