"Much madness is divinest sense," wrote the 19th-century poet Emily Dickinson—"Assent, and you are sane; / Demur—you're straightway dangerous, / And handled with a chain." The chains may have gone, but the language of sanity remains a divisive field; one in which, at least linguistically, the majority's assent can still tend towards brutality.
The word "insane" was first used in 1560 and derives from the Latin insanus. Its etymology—in means "not" and sanus means "sound or healthy"—is a simple clue to the difficulties of discussing mental health. Since ancient times, madness has been defined as a deviation from a norm (the word "madness" itself derives from the Greek mania, "excessive rage"). Unlike physical illness, however, achieving any precision of diagnosis, let alone cure, has proved hugely problematic. Diseases of the mind are a nebulous, atavistically fearful business—one that has repeatedly defied both public comprehension and compassion.
Around 1300, the word idiot was introduced to describe those "natural fools" born incapable of reason. Slightly above this state was imbecility, a term used from the 1620s to indicate "weakness of mind." The 18th century gave us cretin, a term taken from an Alpine dialect, meaning one suffering from a deficiency of thyroid hormones; in America, in 1910, the term moron was coined to describe "an adult with a mental age between eight and 12." Yet all of these terms drifted away from their origins to become increasingly perjorative. And so too have most of the more recent words designed to replace them: retarded, disabled, special. It suggests a troublingly intractable limit to our tolerance. We're demolishing the last asylums, but the prison of public words will take a lot longer to dismantle.
