The term "gaslighting" was coined from the 1938 British play called Gas Light, in which a husband manipulates a wife into thinking she is crazy by slyly changing the intensity of the gas lights in their home when she is left alone. He does this in an attempt to make her believe she cannot trust herself or her memory.
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I honestly didn't realize the term was in pop-cultural usage that far back, god damn
That one goes waaay back.
Social media found it recently but that term goes way back