THINGS changed when April De Angelis turned fifty. Here she was, an independent woman and successful playwright who had grown up with feminism, and who had a teenage daughter who took such hard won advantages for granted in a world where feminism itself had become a dirty word. What had happened, De Angelis wondered, both to her and the world she lived in.

The result of such a mid-life meltdown was Jumpy, a play about the stresses and strains of a fifty-something woman who had grown up protesting against nuclear weapons at Greenham Common, but whose teenage daughter couldn't care less about such things. First world problems such things may be, but Jumpy became a West End hit, and five years on is revived in a new production which opens this week at at the Royal Lyceum Theatre in Edinburgh.

“It came out of experience,” De Angelis says of the play. “I'd turned fifty, and my daughter had turned sixteen the same year, and that made me think about a lot of things, particularly about feminism. When I was growing up feminism was at the centre of everything. My generation reaped the benefits of the Equal Pay Act. I could speak out and say I wanted to be a writer. My mother's generation didn't have that, and it was different again for my daughter's generation. My daughter identifies as a feminist now, but she didn't when she was sixteen. Then she was more interested in clothes and how she looked.

“Now, there's an everyday feminism which hadn't happened five years ago, but there is also more mental illness in young women than there's ever been before, which I'm not surprised about, because there's all this pressure on women about how they should or shouldn't look, and about their shape and size matters.

“I suppose as well I was dealing with the fact that parenting had become much more liberal, and I didn't really know the rules, so was probably over-parenting. Then, turning fifty, and thinking about what that means, and with my daughter turning sixteen, it was a crisis year, really.”

Much of that crisis stemmed from a form of misogyny which has become increasingly vocal of late.

“Men flirt with women and women flirt with men, and that's fine, because that's human nature,” De Angelis says, “but there seems to be an aggressive edge there now sometimes. I can write Jumpy and say it's all going to be okay, but there's all this stuff going on, and you wonder really whether young women are going to be okay.”

De Angelis mentions the case of footballer Ched Evans, whose conviction for rape was recently quashed following a re-trial that saw his alleged victim's sexual history used as evidence.

“That was awful,” she says. “For someone to say, 'oh, you're not a virgin so we can't believe you' is wrong, but I think it is a conservative time. We've got this hard austerity, there are wars going on, and these things breed conservative ideas, so you get some people marching because of a hatred of foreigners.

“With social media now, everything erupts so quickly, and with the Ched Evans thing you had this collective anger from women that was really important. We've all got daughters, and you have to guard yourself and be responsible for each other."

De Angelis began her career as an actress with Monstrous Regiment, the feminist theatre company that existed throughout the 1970s and 1980s. This was at a time when identity politics was high on the agenda in what used to be called alternative theatre, with black, gay and feminist troupes all making their mark.

“Monstrous Regiment and other companies really shaped the theatrical landscape, as well as influencing how people think,” De Angelis says.”At that time, theatre wanted to change the world, and it really was a kind of revolution.”

De Angelis looked to the work of Caryl Churchill and Sarah Daniels, women writers who experimented with form as much as much as content.

“I remember going to see Top Girls,” De Angelis says of Churchill's seminal play that put various iconic women from history in the same room. “It's such a great play, and I was really inspired by it. I think Caryl Churchill really changed the DNA of theatre.”

Monstrous Regiment gave De Angelis her first writing commission, and in 1987, her debut play, Breathless, won an award at the Second Wave Young Women's Writers Festival. Since then, her work has been seen across the world, with Jumpy in particular making its mark internationally.

“The success of Jumpy really opened things up for me,” De Angelis says. “I got commissions off the back of it, and it really shows you what can happen when a play does well.”

Beyond Jumpy, De Angelis is currently working on an adaptation of the novels of Italian writer Elena Ferrante for the Royal Exchange Theatre in Manchester. Ferrante has recently come under public scrutiny, not for her internationally recognised work, but for the fact that she has chosen to write pseudonymously since she first came to prominence in the early 1990s. This year, a male novelist attempted to out Ferrante's real identity in a paper that analysed the historical and geographical content of her work. This month, a male journalist published an article that attempted to identify her through financial transactions regarding property and royalty payments. Such obsessive behaviour can be regarded as another form of violation.

“Isn't it awful” says De Angelis. “I mean, just leave her alone. There's no law that says you can't be anonymous in a way that means you might read the book without thinking about who the author is. Because she's really successful it's really bugged this male journalist, who's said 'how dare she be successful', and raked through her bins. It's about jealousy and revenge.”

Given that she too is a successful female writer, has De Angelis ever encountered jealousy from male colleagues?

“No,” she says. “The theatre is a really liberal, constructive place. Having said that, there still aren't many theatre buildings run by women, and there is still less work put on by women writers than men, and that's still the same in every profession.”

Five years after Jumpy first appeared, De Angelis has changed again. Her fiftieth birthday crisis has passed, and her daughter is no longer a stroppy teenager.

“That sixteen year old who used to stomp into the room in big heels is now a grown up young woman making her own way in the world," De Angelis says. "But young people are so full of life. They challenge you, as they should. It's a battle at times, a love and hate battle, but in the end it's all done for the best.”

Jumpy opens at the Royal Lyceum Theatre, Edinburgh on Thursday and runs to November 12.

www.lyceum.org.uk