For despondency is for souls a grievous torture chamber, unspeakably painful, more fierce and bitter than every ferocity and torment. It imitates the poisonous worm that attacks not only the body but also the soul, and not only the bones but also the mind. It is a continual executioner that not only tears in pieces one’s torso but also mutilates the strength of one’s soul. It is a continuous night, darkness with no light, a tempest, a gale, an unseen fever burning more powerfully than any flame, a war having no relief, a disease which casts a shadow over nearly everything visible. For even the sun and the air seem to be oppressive to those who are suffering from these things, and midday seems to be as darkest night.

—Saint John Chrysostom, Letters to Saint Olympia