Ancients blamed body fluids
This is a retreat of the mind from day to day living. Severe cases can lead to hopelessness and helplessness. It can be difficult to recognize depression in oneself or others. In ancient times, before understanding human physiology (study of the way the body works), many theories were promoted, including the humoral theory by the Greeks.
They believed health and temperament were determined by the proper balance of four body fluids (humors): blood, phlegm (thought to come from the lungs and brain), yellow bile, and black bile. Depression was thought to be caused by excessive black bile. They wrongly believed the fluid came from the spleen (on the left side of the abdominal cavity) rather than the right sided liver. The word melancholia derives from melan (black) and cholia (bile).
It is now known that depression is indeed a problem with imbalances; of chemicals such as serotonin at the synapses of the brain’s nerve cell junctions. We still “humor” the ancient theory. A treat on a hot summer’s day is aptly delivered the The Good Humor Man.