Gaslighting is a psychological manipulation tactic where one person seeks to make another doubt their own perceptions, memories, or reality. This term originates from the 1938 play and subsequent film titled Gas Light, where a husband manipulates his wife into thinking she is going insane by dimming the gas lights and denying it. In relationships, gaslighting can lead to confusion, anxiety, and a loss of self-esteem for the victim. It often involves the manipulator denying facts, twisting information, or using the victim's insecurities against them, ultimately undermining their confidence in their own thoughts and feelings.