Gas Lighting, also referred to as Gas Lamping is an abusive manipulative social ploy to undermine the legitimacy of a complaint or the credibility of the person making the complaint.
It derives its name from an old movie in which an abusive husband attempted to drive his wife to the brink of mental illness by using a variety of manipulative mind bending techniques which were typified by dimming the gas lamps in the home to the point of rendering it hard to see by the low light and then denying that was the case when his wife noticed and complained about the light.
He attributed her perception of the dim lighting to mental illness, suggesting she needed psychiatric help, and insisted that he could see perfectly well.
When others came to inspect the lighting he turned them back up to discredit her complaint and reinforce his assessment of her mental health issues.
Given the classic nature of the abusive technique, the term "Gas Lighting" has evolved in common usage to refer to instances of undermining a legitimate complaint by dismissively suggesting or implying there to be something wrong with the perception of the person making the complaint. (i.e. over-reacting, hypersensitive, paranoid, emotionally weak, intellectually challenged or threatened, etc.)
Gas lighting is a serious form of personal abuse and, over prolonged periods of time causes emotional and psychological breakdown, mental illness, and can lead to suicide.
Gas Lighting is the "go-to" response in Mormon culture to dissidents who become aware of the obvious evidences of the fraud of Mormonism. Utah has been referred to as the "belt buckle of suicide" in the nation, consistently reporting significantly higher than average suicides than national averages.
Gas lighting is invariably used in socially abusive campaigns to discredit and marginalize legitimate complaints together with the technique of character assassination.