Gaslighting

Ingrid Bergman from the 1944 movie Gaslight

Gaslighting is a type of psychological abuse where somebody uses lies or tricks to make another person doubt their memory and mental health. Gaslighting can be anything from an abusive person insisting that the abuse never happened, to setting up strange incidents to confuse the victim.

The word "gaslighting" comes from the play by Patrick Hamilton, Gaslight (1938), and its movie adaptations. In those works a character uses many tricks, including turning the gas lamps lower than normal, to convince his spouse that she is crazy. Since then, the phrase has become a common expression which has also been used in clinical and research literature.