Mélancolie.
ETYM New Lat., from Greek, nerve weakness.
Nervous debility or breakdown.
Obsolete term for nervous exhaustion, covering mild depression and various symptoms of neurosis. Formerly thought to be a bodily malfunction, it is now generally considered to be mental in origin. Dating from the mid-19th century, the term became widely used to describe the symptoms of soldiers returning from the front in World War I.
Nervous breakdown (not in technical use).