“I am more sensitive than other people. Things that other people would not notice awaken a distinct echo in me, and in such moments of lucidity, when I look at myself, I see that I am alone, all alone, all alone.”

"On Going on a Journey"
Table Talk: Essays On Men And Manners http://www.blupete.com/Literature/Essays/TableHazIV.htm (1821-1822)

Source: A Midsummer Night's Dream

Source: The Slow Regard of Silent Things

Source: The Book of Disquiet

Source: A Midsummer Night's Dream

Source: Memories, Dreams, Reflections

As quoted in Vaslav Nijinsky : A Leap into Madness by Peter F. Ostwald, Ch. 8: Playing the Role of a Madman, p. 176
Unsourced variant: I know everyone will say "Nijinsky has gone mad," but I don’t care because I have already played the mad man at home. That is what everyone will think, but they won’t put me in an insane asylum because I dance very well and give money to anyone who asks. People like eccentrics, so they will leave me alone and say I’m a mad clown. I like the mentally ill because I know how to talk to them. When my brother was in an insane asylum, I loved him and he could feel me. His friends liked me. I was eighteen then. I understood the life of a mentally ill person.

Source: Cited in chopin-society.org.uk http://www.chopin-society.org.uk/articles/chopin-britain.htm