Are you crazy or could you be the victim of gaslighting?

His gothic thriller Gaslight is one of the longest-running plays on Broadway, and inspired two film adaptations - including a 1944 version starring Ingrid Bergman - but its influence on modern language is its lasting legacy.

The word "gaslight" has become inescapable. Turn on the TV and it's mentioned on Married at First Sight, or in dramas such as Julia Robert's 2022 series Gaslit. Type "gaslight" into Booktopia and there's almost 100 different books with the word in its title. And in 2020, country group The Chicks - formerly known as The Dixie Chicks - released their first album in more than a decade, titled Gaslighter.

The word is everywhere so it shouldn't be surprising "gaslighting" was Merriam-Webster's word of 2022 after a 1740 per cent increase in searches. At the time it noted it wasn't a single moment that prompted the increase, but in "this age of misinformation - of 'fake news', conspiracy theories, Twitter trolls, and deep fakes - gaslighting has emerged as a word for our time".

Yet this is a word which originated almost a century ago.

Gaslight - originally penned as Gas Light - tells the story of Bella Manningham, a young wife who seemingly has it all. She lives in a nice London home at the turn of last century, with two housekeepers attending to her every need, and a husband, Jack, who appears loving and caring. So why is she so on edge?

As Queensland Theatre tours its latest adaptation of Hamilton's play, audiences once again find themselves wondering if the gas lights are dimming or if Bella is going crazy.

"It's a word that we now use quite frequently in our vocabulary, but most people - especially younger generations - wouldn't think of where the word comes from," says Geraldine Hakewill, who plays Bella in Queensland Theatre's version of the play.

"My character is experiencing strange happenings in the house that she lives in and one of those things is the gas lights go up and down when she hears these noises.

"It's as if somebody's in the house and has turned on another light because the pressure goes down every time you turn an extra light on. But it's unexplained, there's no reason why that's happening. It feels like she's going crazy.

"So there's this idea of the power imbalance and somebody's trying to send another person mad to gain power over them and discredit their version of reality."

While the psychological manipulation that we now refer to as gaslighting is at the centre of this play, the actual term didn't come into use until decades later.

According to the Oxford English Dictionary, the first use was recorded in 1961, with the first medical journal inclusion in British publication The Lancet in 1969. However, in an article titled The Gas-Light Phenomenon, two doctors investigated people misusing the mental health system as a "method of solving family and social problems", not gaslighting itself.

"We describe here two cases in which there were definite plots to remove an unwanted and restricting relative by securing admission to a mental hospital, and one case of an old lady admitted to a mental hospital following induced incontinence," the article reads.

Studies referring to gaslighting, but not focusing on it, have become a theme in the decades since. According to ANU Centre of Social Research Methods research fellow Hayley Boxall, it's partly because gaslighting is difficult to measure.

Boxall has spent the past 10 years studying intimate partner and family violence. In trying to understand how abusive relationships develop, the types of abuse and the barriers to leaving, gaslighting has always been a key part.

"The interesting thing about gaslighting is that it's the imposition of someone's worldview on you," Boxall says.

"Women that I've spoken to who have experienced abuse have spoken about how their partner will physically hit them. When they ask, 'Why did you do that?' the partner goes, 'Oh, I didn't hit you, you tripped'.

"That's a blunt example but when it's non-physical in nature, gaslighting can look like telling women that the abuse they're experiencing is their fault because they're not living up to some kind of expectation that their partner has for them."

According to Merriam-Webster, to gaslight is "to psychologically manipulate a person, usually over an extended period of time, so that the victim questions the validity of their own thoughts, perception of reality, or memories".

The tricky part is recognising it as it's happening. Especially in abusive relationships which are characterised by social isolation.

The people Boxall spoke to throughout her research describe it as like being hit by a big wave or stuck inside a washing machine.

"They don't know what due north is because their partner is so good at convincing them that their worldview is wrong," she says.

Identifying gaslighting often relies on two things. The first is a broader pattern, not a one-off event. The second is hindsight.

"It's mostly in retrospect that people can identify those behaviours as red flags," Boxall says.

"But that's with the benefit of hindsight and after their partners were abusive in ways that are more easily recognisable like they hit me or they called me a name, or they told me I couldn't access my money.

"It is tricky to pin down. Gaslighting in and of itself could be something like a misunderstanding because people do genuinely just misremember things. But when it's within that overall pattern of behaviour, which is really about trying to entrap someone in a relationship or to get them to acquiesce or to comply in some way, that's when you do start seeing people retrospectively going 'That was gaslighting'."

When it comes to gaslighting in intimate relationships, most research concerns those where the male is a perpetrator. That's because statistically women are more likely to be victims of these types of abuse and to be significantly impacted by it.

But that doesn't mean men are more likely to be gaslighters. For example, research into family dynamics suggests both mothers and fathers can be effective gaslighters for their children.

The same can be said about monetary power dynamics. Someone with a higher income is no more likely to be a gaslighter than someone with a lower one.

"A really common scenario that I've come across when I've been speaking to women in Canberra in particular, is that they've had a successful career, and their partner had less of a successful career and their partner's gaslighting has been around how they've had to give up their career to support her," Boxall says.

"These women talk about how their partners were so good at making them feel guilty for having a career and for being interested in their career. They would then spend a lot of their emotional energy trying to make their partner OK, to their detriment."

In Gaslight the audience watches as Jack spends his time convincing his wife her observations are nothing but "wild, wild hallucinations" and dismisses the open flirtation he has with their housekeepers.

He is quick to suggest Bella needs a doctor, implying poor mental health - the plot point that inspired The Gas-Light Phenomenon in the 1960s.

But as Hakewill takes to the stage as Bella each night, the play's themes of vulnerability within relationships come to mind, not the gaslighting.

"It doesn't matter how intelligent you are, human beings are so good at manipulating each other and being manipulated, especially when love is involved," she says.

"Because it's the most vulnerable you'll ever be with another person. The whole point of loving is to allow yourself to be exposed and that leaves you so vulnerable and that's why it's so devastating and common in romantic relationships because it's the most complex dynamic you'll ever have with another human being."

Gaslighting is a type of coercive control, which is slowly being considered a standalone criminal offence across the country. As of July this year, it will be an offence in New South Wales, while in Queensland it will come into effect in 2025. It is covered by the Family Violence Protection Act in Victoria, while the ACT is considering legislative reform following a domestic and family violence review earlier this year.

But of course, gaslighting is not limited to intimate or familial relationships. Gaslighting in the medical field could be a doctor dismissing a patient's symptoms or concerns, or in the workplace it could a boss changing a job description to accuse an employee of underachieving, or an employee stealing credit for someone else's work.

In politics, a politician might deny something previously said or misrepresent information to suit their argument. Donald Trump and the word gaslighter featured side-by-side in countless commentary pieces during his time as US president. Many credit it for the greater recognition of gaslighting, even if people don't quite understand what it is.

"Everyone has examples of a boss who was a gaslighter, a family member, a friend. But I think we use the term without really having a very specific definition in mind," Boxall says.

"We're aware of it, but we are still grappling with what it is and how to measure it. That's the next stage for our understanding of it - to try to get more specific with it."

But this prevalence does mean that the play that inspired the word has a completely different feel in 2024. A clued-up audience takes some of the suspense out of the original plot.

This is why Queensland Theatre's version has been adapted by Canadian writers Johnna Wright and Patty Jamieson. By taking out characters and adjusting plotlines, it becomes less about who is a gaslighter, and more about how many gaslighters there are, and who are the victims.

"It plays with who's gaslighting whom, and the two maids in the house help and hinder at different points," Hakewill said.

"It's very unclear whose allegiance they have and what their role is in the story until the end. What's wonderful about this adaptation is it does keep people guessing right until the end. We had an audience last night ... and a lot of them said they still didn't know what was happening until it was revealed."

Gaslight will be at the Canberra Theatre from May 15 to 19. Tickets from canberratheatre.com.au. It will be at Newcastle's Civic Theatre from June 19 to 23. Tickets from civictheatrenewcastle.com.au.