The term “gaslighting” comes from a 1938 British play called Gas Light by Patrick Hamilton, in which a husband systematically manipulates his wife into believing she is losing her mind. The gas lamps in their home are central to the plot, and the play’s title eventually became shorthand for a specific kind of psychological manipulation that persists to this day.
The Play That Started It All
Set in fog-bound London in 1880, Gas Light follows Jack Manningham and his wife Bella. Jack is secretly searching the sealed-off apartment above their home each night, looking for jewels belonging to a woman he murdered years earlier. Every time he lights the gas lamps in the upstairs apartment, the gas supply to the rest of the building drops, causing the lights downstairs to visibly dim.
Bella notices the flickering lights. She hears footsteps overhead. But when she tells Jack, he insists she’s imagining things. The dimming gaslights become a physical symbol of what he’s doing to her psychologically: she can see the evidence right in front of her, yet the person she trusts most tells her it isn’t real. Jack’s campaign goes beyond the lights. He works to convince Bella she is going insane, denying things she knows to be true, until a police detective named Rough arrives and helps her understand that everything she perceived was accurate all along.
How the 1944 Film Cemented the Idea
A 1944 Hollywood adaptation starring Ingrid Bergman brought the story to a much wider audience and added layers to the manipulation tactics. In the film, the husband Gregory doesn’t just deny what his wife Paula sees. He actively engineers false evidence against her. He hides paintings and accuses her of moving them. He slips his pocket watch into her handbag, then publicly accuses her of stealing it, causing her to break down in front of other people. He isolates her from the outside world, convincing her she’s too unstable to be seen in public. He tells her that her mother died in an asylum, implying she’s headed for the same fate. He even claims a letter she discovered never existed.
The gaslight detail remains: when Gregory goes to the attic to search for hidden jewels, lighting those fixtures reduces gas flow to the rest of the house, dimming the downstairs lamps. Paula notices, Gregory denies it, and the cycle of doubt deepens. The film was a critical success, and the image of those flickering gas lamps became culturally inseparable from the pattern of abuse it depicted.
From Stage Drama to Psychology
Psychologists didn’t formally borrow the term until 1969, when two researchers, Barton and Whitehead, published a paper in The Lancet describing what they called “the gas-light phenomenon.” Their case studies documented real-world manipulation designed to make someone appear mentally unfit. In one case, a wife tried to frame her husband as violent so she could leave with her lover. In another, a retirement home manager gave laxatives to a resident, then referred her to a psychiatric hospital for apparent incontinence and dementia. Each case involved one person deliberately distorting another’s reality for personal gain.
Gaslighting is not a formal diagnosis in any edition of the DSM, the manual clinicians use to classify mental health conditions. It’s a descriptive term for a pattern of behavior, not a clinical disorder. But its absence from diagnostic manuals hasn’t limited its usefulness. Therapists, researchers, and advocates use it widely to identify a specific form of manipulation that other words like “lying” or “deception” don’t fully capture.
What Makes Gaslighting Different From Lying
Ordinary lying is about hiding the truth. Gaslighting goes further: it aims to make you distrust your own ability to perceive the truth. The goal isn’t just to deceive but to undermine your confidence in your own memory, judgment, and sanity. It functions by convincing you that what you’re experiencing isn’t real or isn’t important, then blaming you for your own confusion.
A key element is what researchers call “credibility slashing.” The gaslighter works to make the victim seem unreliable to other people, appealing to social norms or stereotypes to do it. If the victim’s friends, family, or coworkers start to see them as unstable, the isolation deepens and the manipulation becomes harder to escape. This is why gaslighting thrives on power imbalances. It shows up most often in relationships where one person already holds more social, financial, or institutional power: domestic violence situations, parent-child dynamics, and workplaces where racial or gender discrimination creates unequal footing.
Common gaslighting tactics map directly back to the play’s core dynamic. Phrases like “that never happened,” “you’re imagining things,” and “you’re too sensitive” all serve the same function as Jack Manningham telling Bella the lights weren’t dimming. Other recognizable patterns include shifting blame onto the victim, withholding information or refusing to engage with a concern, disguising cruelty as humor (“it was just a joke”), and enlisting others to reinforce the victim’s self-doubt (“everyone else thinks you’re crazy”).
Why the Term Exploded in Popularity
For decades, “gaslighting” remained mostly within psychology and advocacy circles. That changed dramatically in the 2010s and 2020s. Merriam-Webster named it the 2022 Word of the Year after lookups for the term surged 1,740% over the previous year, with consistently high interest across all twelve months rather than a single spike.
The dictionary noted that gaslighting had become uniquely suited to an era of misinformation, conspiracy theories, and deepfakes. Unlike “lying,” which typically describes deception between individuals, or “fraud,” which tends to involve organizations, gaslighting applies to both personal relationships and political contexts. It captures something specific: the deliberate, sustained effort to make people doubt what they can plainly see.
How the Term Has Expanded
The word now extends well beyond romantic relationships. “Medical gaslighting” describes situations where healthcare providers dismiss or minimize a patient’s symptoms. According to Harvard Health Publishing, this can look like a clinician who interrupts you, blames your symptoms on your age or weight without investigation, or attributes physical complaints to anxiety without running tests. A typical example: a 70-year-old reports unusual fatigue and body aches, and the doctor says it’s probably just aging without ordering any bloodwork.
Medical gaslighting is more likely to affect women and people of color, driven by unconscious bias in clinical settings. It also tends to occur with conditions that lack straightforward diagnostic tests, like long COVID, where the absence of a clear biomarker makes it easier for providers to question whether symptoms are real. The pattern mirrors the original play with striking precision: someone experiences something genuine, reports it to a person in a position of authority, and is told it isn’t happening.
That through-line, from a dimming gas lamp in a fictional Victorian apartment to a modern doctor’s office, is exactly why the term has endured. It names something people recognize instantly once they have the word for it.