Depression has not always been as well understood as it is today. In Ancient Greece depression was thought to be due to an imbalance of body fluids. As early as the seventeenth century, though, it was proposed that depression, which was called âmelancholyâ, could be overcome by a healthy diet, good sleep, music, "meaningful work", and talking about the problem with a friend. In the nineteenth and twentieth centuries depression became more of a scientific problem than a philosophical one, and in 1980 it was officially classified as a disease.