Sylvia Plath in The Bell Jar
I hadn't slept for seven nights....
The reason I hadn't washed my clothes or my hair was because it seemed so silly.
I saw the days of the year stretching ahead like a series of bright, white boxes, and seperating one box from another was sleep, like a black shade. Only for me, the long perspective of shades that set off one box from the next had suddenly snapped up, and I could see day after day after day glaring ahead of me like a white, broad, infinitely desolate avenue.
It seemed silly to was one day when I would only have to wash again the next.
It made me tried just to think of it.
I wanted to do everything once and for all and be through with it.
In Billy Budd, Salior, the novelist Herman Melville, who himself suffered from recurrent and severe depressive episode, posed the problem of distinguishing between normal and abnormal moods metaphorically (and with considerable poetic license about the order of colors in the rainbow):
Who in the rainbow can draw the line where the violet tint ends and the orange tint begins? Distinctly we see the difference of the colors, but where exactly does the one first blendingly enter into the other? So with sanity and insanity.