Grzegorz Jarzyna has a set of photographs from the rehearsals of 4.48 Psychosis. If ever you were to run a class about body language they would be your perfect visual aids. He and his cast have turned in on themselves, becoming morose and introspective, projecting bad vibes and animosity. They are not having the cheeriest of times.

You can hardly blame them. Sarah Kane’s play is the closest the theatre comes to a suicide note. She wrote it ten years ago, a 40-page dramatic poem with no named characters, spare, fluid, elliptical and burning with the lived experience of a bipolar disorder. The voices that emerge from the dream-like script are of doctors, nurses, lovers and friends, all in their helpless way concerned for the wellbeing of a central character hell-bent on hanging herself at 4.48am. According to her friend, the Scottish playwright David Greig, that’s the time at which Kane would wake up: ‘In a moment of great clarity, a moment when the confusions of psychosis seem to evaporate.’

In the play, it is also the time when ‘delusion is at its strongest’ and the character is most likely to harm herself. In February 1999, not long after she had completed the script, the 28-year-old playwright brought her life to an end. She didn’t live to see the play’s premiere at London’s Royal Court in 2000, marking the sad conclusion of a brief but luminous stage career that began in 1995 with the controversial Blasted (‘this disgusting feast of filth’, frothed the Daily Mail) and continued with Phaedra’s Love, Cleansed and Crave.

Her theatrical arrival was met by a wave of outrage, but by the time of her death, no less a figure than Harold Pinter was lauding her as a poet. From the start, Pinter had recognised she was ‘facing something actual and true and ugly and painful’. That was no less the case in the Bosnian-inspired violence of Blasted than it was in the howl of desperation that was 4.48 Psychosis.

‘It was very difficult to rehearse,’ says Jarzyna. ‘Somehow we got the depression of the main actress. I have some pictures and you can see we’re not talking. There was not so much communication.’ None of which suggests 4.48 Psychosis is a suitable first-date play. But to judge from the audience at Jarzyna’s Warsaw theatre, neither does it appeal only to gloomy Goths. Teatr Rozmaitosci, a former variety palace, is not much to look at but, as the home of TR Warszawa, it’s a magnet for the kind of youthful, intelligent and fashionable crowd that marketing managers elsewhere can only dream of.

On a Friday night in January, there’s a queue of young people hoping for returns and a sense in the air that this is where the energy lies in Poland’s post-communist theatre scene. ‘Grzegorz Jarzyna has single-handedly championed that company and that space into existence,’ says Edinburgh International Festival director Jonathan Mills, who has also programmed the company’s production of The Dybbuk. ‘They have an incredibly lively audience and those actors are very much the stars of the Polish screen.’
It’s a feat Jarzyna, a fresh-faced 40-year-old with deep brown eyes, has pulled off over the last ten years. He’s done it in two ways. The first is to build on the strengths of an acting ensemble who started as a group of friends and have gone on to become major names in Poland, not least in the case of the stunningly beautiful Magdalena Cielecka, star of 4.48 Psychosis, cover model and darling of the gossip magazines.

The second way is to develop a repertoire that has introduced Warsaw audiences to the ‘in yer face’ generation of which Kane was a part. By offering a diet of Mark Ravenhill’s Shopping and Fucking, Brad Fraser’s Unidentified Human Remains and the Dogme adaptation Festen, alongside surrealist SI Witkiewicz and some more familiar Polish fare, Jarzyna has created a theatre where a young, studenty generation wants to hang out.

Of course, this would count for little if the work wasn’t up to scratch, but he is nothing if not talented. It’s a talent he does not shout about. Over dinner with a group of theatre people - including, oddly enough, Simon Callow who just happens to be in town - the director is thoughtful and questioning where many in his position would be loud and dominant. It’s this sensitivity that comes across in his 4.48 Psychosis in which he draws on Kane’s own life story to make sense of the elliptical text, which he has re-ordered to suit his own ends.

‘My task was to tell the story,’ he says, sitting at a desk in his office. ‘When I looked at the text I realised there were no stage directions and even in passages of dialogue you didn’t know who was speaking, or how many people were. So I understood that it was completely freeform, something very open. From my point of view, I wanted to put it into order so I could tell a story from beginning to end.

‘When I studied what happened to Sarah Kane, her relationships and the people who knew her, I discovered that all of this period of her life was in the text: the meeting with the girlfriend, the friend, the doctor, going to the hospital, having psychiatric tests. I put my own stamp with the story on it so that I understood the narrative.’

Dealing with such delicate material, Jarzyna was careful to give an honest representation of mental illness. ‘I have not had mental illness myself, but my friends have,’ says the director, a graduate in philosophy from Krakow’s Jagiellonski University. ‘Many artists have some problem from childhood and many people that I know very closely have mental problems. Many actors treat the theatre as some kind of therapy. We asked a psychiatrist to study the text and he recognised what kind of schizophrenia it was. He said that this case could be healed with therapy and explained to us many lines in the play that we didn’t understand. For example, the idea that she feels 80 years old, which is something people can feel when they are very depressed.’

The psychiatrist proceeded to ask Jarzyna whether anything depressive had ever happened in his life. ‘I told him about the death of my father and how I didn’t know what was going on and couldn’t react for two days. He asked me to imagine those two days spread over four months. You can’t sleep, dream or eat. It was an example that showed me the scale of the problem. Every day the same with no escape.’

For all the play’s bleak subject matter, however, the production is full of light and shade, showing the woman’s joyful escape into sex and alcohol, just as much as her violent depression. Lest we become too comfortable with the hypnotic pace and Cielecka’s superb performance, Jarzyna repeatedly turns the tables on us. When Cielecka cries: ‘fuck you all!’ it’s directed at us as if to challenge our voyeurism. As her despair intensifies, it feels as though we in the audience are letting her down. ‘Watch me vanish,’ she whispers as the house lights come up, leaving us at a loss about when - or even whether - to applaud.

‘When the audience is completely silent, I know that it’s working,’ says Jarzyna. ‘We can talk about such cases of mental illness and be quite smart, but there is a moment when you are in one room face to face with a person having a big psychological crisis and that’s a completely different story. You don’t know what’s going on. You get crazy as well. You don’t know what to do: shout or say nothing. When I had that experience, I didn’t know what to do, whether to call a doctor . . . I really didn’t know. I was frightened. I was a coward. That experience is very strong and that’s what I wanted to share.’

4.48 Psychosis, King’s Theatre, Leven Street, 0131 473 2000, Fri 15-Sun 17 Aug, 8pm, £10-£25.