What I had begun to discover is that, mysteriously and in ways that are totally remote from normal experience, the grey drizzle of horror induced by depression takes on the quality of physical pain. But it is not an immediately identifiable pain, like that of a broken limb. It may be more accurate to say that despair, owing to some evil trick played upon the sick brain by the inhabiting psyche, comes to resemble the diabolical discomfort of being imprisoned in a fiercely overheated room. And because no breeze stirs this cauldron, because there is no escape from the smothering confinement, it is natural that the victim begins to think ceaselessly of oblivion

William Styron