The term “gaslighting” comes from Patrick Hamilton’s work Gas Light (1938), a play that was adapted into two movies in 1940 and 1944. The basic plot of the play and movies deals with a husband who systematically manipulates and psychologically abuses his wife by trying to convince her she is insane. He does this by changing small elements of their environment (such as the dimming the representative gas lights of the house) and then insisting she’s mistaken or misremembering details of their environment when she points out what is different.
Since the 1960s, the term “gaslighting” has been used colloquially to describe efforts in manipulating someone else’s sense of reality. Sociopaths often utilizing gaslighting to cast doubt unto the perceptions of those they wish to victimize. This is why people who have sociopathic tendencies can charmingly lie about any wrongdoing, while simultaneously exploiting other people.
However, gaslighting is most prevalent as a form of emotional abuse between partners, friends, lovers, or family members. It creates a power structure within a relationship wherein the person being abused is denied access to true mental agency, through repetitive disempowering words and actions by the abuser. Because victims of gaslighting often question their own perceptions of events, they are more likely to stay in an abusive relationship. People who have been emotionally abused in this way may even believe that that problems within their relationship are their fault, when it is most certainly not. This particular brand of emotional abuse is especially toxic in that it’s hard to pinpoint and, sometimes, even harder to talk about.
The National Domestic Violence Hotline has an article about gaslighting that is worth a read. It outlines signs of emotional abuse within interpersonal relationships as written by psychoanalyst Robin Sterm, Ph.D, in a clear and concise way.