Charles Boyer and Ingrid Bergman

What is gaslighting precisely? It takes its name from a play and then a 1944 movie called Gaslight starring Charles Boyer and Ingrid Bergman. In it, Boyer manipulates Bergman and distracts her from his criminality by trying to convince her that she is going insane. And that’s what gaslighters do: They make the target believe that his or her grip on reality is tenuous at best and non-existent at worst. The most common tactics are insisting that something that happened didn’t, dismissing a claim by saying it was simply imagined, or telling the person flat out that she or he is losing it or crazy. Gaslighters exploit their target’s fears, insecurities, vulnerabilities, and neediness to their own ends. source