"See, this is another sign of your tragic space dementia, all paranoid and crotchety. Breaks the heart."
"They think I'm crazy. But I know better. It is not I who am crazy. It is I who am mad!"
Even unknown, and monster-peopled by superstition, Earth had not been as cruel an environment as space; nor had a caravel been as unnatural as a spaceship. Minds could never have disintegrated as quickly in mid-ocean as between the stars.
— The Burning Bridge by Poul Anderson.
"I fear that when our master reached for the stars, he came down with a touch of...space madness."
"It is so dark around, no life, no hope, no sound, no chance of seeing home again ... Somebody help me I'm missing, somebody help me I'm missing now touch with my mind, I have no frame ... no people around, no-one to touch. I am now quite alone, part of a vacant time-zone, here floating in the void..."