My existence is a terrible burden: I would have cast it off long ago if I hadn't been conducting the most instructive tests and experiments in the intellectual and ethical domains precisely during this period of illness and almost total deprivation – this joyfulness, thirsting after knowledge, brings me to heights where I triumph over all martyrdoms and all hopelessness. On the whole, I'm happier than ever before in my life. And yet! Constant pain, a feeling of being half-paralyzed, a condition closely related to seasickness, during which I find it difficult to speak – this feeling lasts several hours a day. For my diversion i have raging seizures (the most recent one forced me to vomit for three days and three nights; I thirsted after death). Can't read! Only seldom can I write! Can't deal with my follows! Can't listen to music!

Nietzsche, letter to Otto Eiser, January 1980