“Misery loves company, and madness calls it forth.”

Source: The Laundry Files, The Labyrinth Index (2018), Chapter 10, “Flight Plan” (p. 296)

Source: The Stand

Introductio ad prudentiam: Part II (1727), Gnomologia (1732)

Source: Clockwork Prince

Quand nous perdons un être aimé, ce qui nous fait pleurer les larmes qui ne soulagent point, c'est le souvenir des moments où nous ne l'avons pas assez aimé.
Wisdom and Destiny (1898)

Remark after being incarcerated in Bedlam for five years, as quoted in the Introduction of A Social History of Madness : The World Through the Eyes of the Insane (1987) by Roy Porter; also in "The Madness of King Jesus : Why was Jesus Put to Death, but his Followers were not?" by Justin J. Meggitt in Journal for the Study of the New Testament, Vol. 29, No. 4 (June 2007) http://jnt.sagepub.com/content/29/4/379.abstract.

La ciudad de la Luna (2009)

Yea and Nay : A series of lectures and counter-lectures given at the London school of economics in aid of the hospitals of London (1923) edited by C David Stelling, Section IV, Poetry and Modern Poetry
Context: Let us speak of our madness. We are always being called mad. If we are mad — we and our brothers in America who are walking hand in hand with us in the vanguard of progress — at least we are mad in company with most of our great predecessors and all the most intelligent foreigners. Beethoven, Schumann, and Wagner, Shelley, Blake, Keats, Coleridge, Wordsworth were all mad in turn. We shall be proud to join them in the Asylum to which they are now consigned.