But I know for a fact that "retarded" and "retardation" have not been replaced; they're being phased out for political reasons, but the terms still have a specific meaning and are definitely still in use clinically.
What I doubt (lacking real evidence) is that the person-noun form "retard" -- think about phrases like "discharging a retard", "managing retard behavior", "a unit full of retards" -- was ever in widespread clinical use, as "idiot" or "imbecile" were in the past. The move to stop using those terms was not about just changing the word, but also recognizing mental disorders as something distinct from a person's inherent nature.
(Again, similar to the move from "negroes" to "black people". Either can be used pejoratively, but the former is arguably intrinsically offensive.)
What I doubt (lacking real evidence) is that the person-noun form "retard" -- think about phrases like "discharging a retard", "managing retard behavior", "a unit full of retards" -- was ever in widespread clinical use, as "idiot" or "imbecile" were in the past. The move to stop using those terms was not about just changing the word, but also recognizing mental disorders as something distinct from a person's inherent nature.
(Again, similar to the move from "negroes" to "black people". Either can be used pejoratively, but the former is arguably intrinsically offensive.)