Look up the movie, made from a play, called Gaslight, from the 1930s with Ingrid Bergman and Joseph Cotton. It’s about a manipulative murderer, who marries his young step-daughter, then goes looking for the treasure in the attic. The lights dim every time he goes up there, but he says oh, no the lights are fine, etc., and ultimately convinces poor Ingrid and all their friends that she is insane and cannot trust herself, and he (almost) gets away with murder again. A must see noir movie for us gaslighted folks. this is how it came into the language of psychology.