Alienist

An alienist is "one who treats mental diseases; a mental pathologist; a 'mad doctor,'" according to The Oxford English Dictionary. The OED also defines "alienation" as in this sense as "mental alienation; withdrawal, loss, or derangement of mental faculties; insanity." The insane were thought estranged (alienated) from their normal faculties. The root of "alienist" is the Latin "alienare," to make strange. The word "alienist" came across the Channel to England from France where "aliéné" meant insane and an "aliéniste" was one who cared for the mentally ill: a psychiatrist.

The Other as the natural interlocutor of the psychiatrist.