I've found Conrad Aiken's "Silent Snow, Secret Snow" and know that it resonates with me. It is a perfect illustration of the internal logic of a person tired of external stimuli, who finds his internal world more alluring and somehow safer. This is a boy who lives more vividly within, rather than externally, near his skin.
The story also illustrates how easy it is to lose touch with reality if we allow it. If we look deeply into the well of ourselves, we see no reflection, but a secret stream that can carry us away.
In one of my stories, I had a character, deceased but part of a hallucination, chide her son for wanting to immerse himself in his strange notions, as she had done before dying: "It will drown you if you put your whole head in." And he answers: "But what if I just want to dip my face in to see what the other world looks like?"
There's a surprising underlying logic to insanity that, while idiosyncratic to every person, still draws so many things together.