Oliver Sacks, writing on mania and manic depressive disorder in the New York Review of Books:
One may call it mania, madness, or psychosis–a chemical imbalance in the brain–but it presents itself as energy of a primordial sort. Greenberg likens it to “being in the presence of a rare force of nature, such as a great blizzard or flood: destructive, but in its way astounding too.” Such unbridled energy can resemble that of creativity or inspiration or genius–this, indeed, is what Sally feels is rushing through her–not an illness, but the apotheosis of health, the release of a deep, previously suppressed self.
These are the paradoxes that surround what Hughlings Jackson, the nineteenth-century neurologist, called “super-positive” states: they betoken disorder, imbalance in the nervous system, but their energy, their euphoria, makes them feel like supreme health. Some patients may achieve a startled insight into this, as did one patient of mine, a very old lady with neurosyphilis. Becoming more and more vivacious in her early nineties, she said to herself, “You’re feeling too well, you must be ill.” George Eliot, similarly, spoke of herself as feeling “dangerously well” before the onset of her migraine attacks.
I would love for Sacks to create a commonplace book, featuring all those quotes that he so effortlessly places throughout his prose. (Auden wrote a great one.) Speaking of manic depression, I’ve always been intrigued by Virginia Woolf’s bi-polar/manic-depressive disorder, as she typically experienced a burst of creativity after suffering a bout of depressive symptoms. To the Lighthouse, for instance, was written in a short burst of inspiration after a particularly punishing summer of illness. (Woolf would later joke that writing that novel was the closest she would ever come to undergoing psychoanalysis.)