This term is used in the 1944 Ingrid Bergman film Gaslight, in which a husband purposefully drives his wife insane by flickering lights, making noises in the attic, and then claiming the very real experience was all in her head.

invalidation is crazy-making, and it is also at the root of gaslighting, where victims' feelings are purposely denied or manipulated in order to make them question their sanity.