In a conference call on Tuesday, Dr. Regier, Dr. Kupfer and several other members of the task force outlined their favored revisions. The task force favored making semantic changes that some psychiatrists have long argued for, trading the term “mental retardation” for “intellectual disability,” for instance, and “substance abuse” for “addiction."What this implies is that "mental retardation" is still on the book as a valid diagnosis. It isn't an outmoded and discarded remnant of past medical practice that merely lives on in the pubic consciousness. I had been under the impression that the term was no longer used in the psychiatric community.
Now this is not to defend Rahm Emmanuel, nor Rush Limbaugh, nor to attack Sarah Palin, though I have a strong disliking of all three. It's merely to point out that "mentally retarded" is still a valid scientific term. That may change when the new edition comes out, but for the time being, politically correct or not, there are contexts other than satire where the use of that description is accurate and appropriate.
Followup, 1:45 PM: The Guardian has an article on the same topic and describing the importance, difficulty and sensitivity of this work in even more detail.