This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
For roughly two thousand years, Western medicine's explanation for what we now call depression rested on a single organ system that does not, in the way the ancient Greeks imagined it, exist. Melancholia, the condition's ancient name, comes from melas, black, and khole, bile, and reflected the belief that an excess of one of the body's four humors caused a specific, describable set of symptoms. Hippocrates himself described the condition in his Aphorisms, characterizing fears and despondencies that, when they persist for a long time, mark the disease, and the theory persisted through Galen and into the early modern period essentially unchanged in its basic logic.
The word depression itself is a much later arrival to psychiatry, and its path there is oddly indirect. It entered general English in the seventeenth century simply meaning low spirits, with no clinical weight attached, and stayed a loose figure of speech for two centuries. Its first specifically psychiatric, clinical use is credited to French psychiatrist Louis Delasiauve in 1856; even then it took until the close of the nineteenth century for depression to fully displace melancholia as medicine's standard name for the condition.