Any doubts about whether Heathers still appeals to people 30 years after its release were answered by a recent trip to Heathers: The Musical. I’m old enough to remember seeing Heathers in the cinema in 1989, but looking around the auditorium, my generation was easily in the minority. It was overwhelmingly young adults and teenagers, mostly female, many of them dressed in full Heather regalia: shoulder-padded blazers, knee-high socks, tartan, primary colours and, of course, scrunchies. The movie’s pitch-black comedy has been brightened somewhat on its journey to the 21st-century stage, with the addition of musical numbers such as Freeze Your Brain (on the transformative properties of 7/11 slushies) and My Dead Gay Son (in which a double funeral becomes an anthem to inclusivity). The show, which transfers to the West End in September, was raucously received. As a Heather would say, it was very.

Clearly, one reason Heathers endures is its compendium of high-1980s style tips. Another is its arsenal of eminently quotable lines (“Well fuck me gently with a chainsaw”, “What is your damage, Heather?” “Did you have a brain tumour for breakfast?”). But, like all good cult movies, Heathers went further than was generally considered acceptable, and in doing so it captured what other movies of its era missed. This was the era of Reagan’s “Morning in America”: a facade of cheery, 1950s-style conservatism veiling “greed is good” capitalist ruthlessness. It was also a time when the Brat Pack and John Hughes movies such as The Breakfast Club and Pretty in Pink ruled the teen roost. Hughes could go deep but he rarely went dark. Heathers, on the other hand, is a black comedy about America’s black soul.

“We didn’t think things were as fun as everybody else did,” says Heathers’ director, Michael Lehmann. Lehmann is as surprised as anyone to still be talking about Heathers. It was his first movie, working to a script by another first-timer, Daniel Waters. “We were looking at the John Hughes films and saying ‘This is bullshit!’ The movies are fun, we like them, but we didn’t think they really represented the truly cruel nature of interpersonal behaviour in high school.”

For the uninitiated, Heathers is the tale of teenage Veronica (played in the movie by Winona Ryder), who is caught between the clique of vicious, immaculately attired in-girls (all named Heather), and the charming outsider rebel, JD (Christian Slater), who really wants to kill everybody – and partially succeeds, with Veronica’s help. Heathers touched on, and laughed at, suicide, self-harm, eating disorders, school shootings, peer group pressure, fat-shaming and even rape. It is high school red in tooth and claw, and scrunchie.

“People look at the movie now and go, ‘Wow. Did people really dress like that?’ We were saying the same thing at the time!” says Lehmann. As with its fashion sense, Heathers exaggerated what was already there. “One of the reasons the movie still has an afterlife is it’s such a perverse vision of what people looked like and acted like at the time. And it’s not that far from the way things really were but stylised enough to make it clear that we were doing satire, you know?”

Facebook Twitter Pinterest Ryder in Heathers. Photograph: Snap Stills/Rex/Shutterstock

Needless to say, not everybody in 1980s America saw the funny side. Heathers was not a box-office hit. “People were outraged: ‘How dare you make a comedy about teenage suicide?’ Well I didn’t make a comedy about teenage suicide,” says Lehmann (nobody in Heathers actually commits suicide). “There were plenty of people at the time who thought the humour was irresponsible, and that the choice of subject was not something that should be put up for satire and, you know, I just rolled my eyes and said the most horrific topics should be the ones that are best suited to satire.”

Not all of Heathers’ taboo-busting has aged well, Lehmann admits. The idea of shooting a couple of jocks then making it look like a gay suicide pact (hence the father’s declaration: “I love my dead gay son!”) would not really wash today. Nor would the image of a trench-coated teen casually waving around a gun in the cafeteria. This was 10 years before the Columbine massacre, when jokes about school shootings were still in the realms of far-fetched fantasy.

The movie is also somewhat blithe when it comes to matters of sexual assault. Three characters try to rape Veronica over the course of the movie. There is also an uncomfortable scene where the two jocks take Veronica and weak-willed Heather McNamara (played by Lisanne Falk) on a disastrous double date involving cow-tipping in a field. While Slater turns up to rescue Veronica, and while they converse in the foreground, Heather McNamara is being sexually molested in the background.

Lisanne Falk winces when she looks back on that scene, she says: “I thought we were doing this funny scene in the background. I’m not going to call myself stupid but I want to say ‘naive’. I didn’t over-think it, but I look at it now and think: ‘I guess that was pretty horrible.’” Many teenage actors, including Heather Graham and Jennifer Connelly, turned down roles in Heathers, or rather, their parents didn’t let them do it.

Ryder was just 15 when the shoot began, recalls Michael Lehmann, but she “got it”. “She was sent the script and she immediately told all her representatives that she was going to do it no matter what, even though they advised her up and down not to.” Falk was actually 23 (though she didn’t tell them that until after she got the part), and therefore didn’t need her parents’ permission. “I loved the dialogue. We were all really into it, it was like nothing we’d ever auditioned for or seen in movies before.” Other actors of the era, such as Molly Ringwald, have reminisced on the misogynist and predatory climate of the teen Hollywood in the 1980s but Falk, who had also worked as a child model, has happy memories of making Heathers. “I had a ball! I loved every second. I hung out a lot of the time on the set when I wasn’t working cos they were shooting around where I lived [in Los Angeles]. And I formed a really strong bond with Winona. We had the same sense of humour.”

Facebook Twitter Pinterest Axed TV series Heathers... (from left): Grace Victoria Cox, Melanie Elainie Field, Brendan Scannell and Jasmine Mathews. Photograph: Allstar/Lakeshore Entertainment

Falk now has a 14-year-old daughter of her own. Having held out for as long as possible, they sat down to watch Heathers a couple of weeks ago “because all her friends had seen it”. Her daughter’s reaction? “She was really weirded out seeing her mother on screen, of course,” says Falk, “but she just laughed like, ‘Oh my god, these people still exist!’ I guess they will always exist, and that’s the thing we talked about afterwards, being able to find your own identity when you have all these people trying to figure out who they are but then end up following what they think is popular. She tells me when they have non-uniform days at school – it’s a girls’ school – all the girls come in and they’re wearing the same outfits. It’s that thing where you think you’re being different but you’re all being the same because it’s safer.”

As well as capturing its time, Heathers caught something universal, then, but bringing it into the modern day has required some adjustments. Heathers: The Musical is a brighter, more optimistic proposition than the movie, with more of a female self-empowerment theme and less in the way of transgressive satire. The sexual assault incidents have been removed, fewer guns are waved around, Veronica no longer burns her hand with a cigarette in self-loathing. It hits the spot with fans, but others have likened it to “a mere Glee episode about suicide”.

Facebook Twitter Pinterest Heathers: The Musical. Photograph: Chad Batka/AP

The musical is not the only recent repackaging of Heathers; there is also Heathers the TV series. Set in the present day, it is billed as “a satirical comedy that takes creative risks in dealing with many of society’s most challenging subjects, ranging from personal identity to race and socio-economic status to gun violence”. The show makes some drastic changes to the original set-up: the new Heathers of the piece are no longer all thin, privileged white girls; instead, one is a plus-sized girl, one is a black lesbian, and one is a genderqueer male (Veronica is white and blonde). Thus, the original film’s political satire is turned on its head. It was applauded by far-right commentators, which was probably not the intention. As one review put it: “If you believe that kids these days are fragile ‘snowflakes’, that political correctness is running amok, and that LGBT people are now society’s true bullies, this new Heathers is the show for you.”

The series was scheduled to air this March but was postponed at the last minute in light of the high-school shooting in Parkland, Florida. Three months later, after the Santa Fe school shooting, the show was pulled from US schedules altogether. “The combination of a high school show with these very dark moments didn’t feel right,” said the studio, although it has been made available, without fanfare, in some European and African countries – where presumably the far-right vibes play better. A sequel to Heathers the movie was also talked about for many years, says Michael Lehmann. Winona Ryder was especially keen. “Her idea was that the Heathers had all gone to work in Washington DC.” In its absence, some of that Heathers legacy has percolated down through the generations, in teen movies such as Clueless, Mean Girls and Election, or this year’s Thoroughbreds, about two privileged white girls who coolly plot a murder.

Now Lehmann wonders if we’re not actually living in a Heathers sequel: “I watch the American political news and I can’t believe how much it’s like high school! I watch Kellyanne Conway and Sarah Huckabee Sanders: they are Heathers – absolutely flat out. Ivanka is certainly a Heather, and Donald Trump himself is like a big Heather!” There’s something about the Trump establishment’s combination of pitiless, cliquey belligerence and presentational power-dressing that suggests teenage girls aren’t the only ones who’ve been using Heathers as a style manual. In an irony Veronica would surely appreciate, the jocks and the bullies and the mean girls triumphed after all. That’s not to suggest someone needs to blow up the White House and make it look like a mass suicide, but it’s certainly fuel for some kind of rebellion.

The 30th anniversary re-release of Heathers is out in cinemas on Friday 10 August