CAN anyone give me a logical explanation as to why it is apparently politically correct to describe someone as "mentally ill", but not to describe anyone as "mentally handicapped"?

The Shorter Oxford English Dictionary defines "mental" as "of or pertaining to the mind" - surely this applies to both mental illness and mental handicap - or should we be referring to the mentally ill as "persons with disordered thought processes", to match the equally cumbersome, politically correct, "persons with learning disabilities"?

W Alan Heaton-Ward