Has comedian Kim Noble exploited his mental illness to create one of the most shocking stand-up shows ever?

When I went to see the comedian Jon Richardson at the Edinburgh Fringe this year, he had just been nominated for the Edinburgh Comedy Award. But at this gig, the poor man was too distracted to perform his act. "I've just seen this show," he gibbered at his audience. "I can't get it out of my head." He wasn't alone: everyone in town was talking about the live-art-meets-stand-up event Kim Noble Will Die. Critics called it "An hour I will remember for all of my life" and "A sublime [and] profound work of art." "But all my posters," says Noble, "were ripped up and graffiti'd with 'absolute toss', 'rubbish', and 'insulting bollocks'. So my show isn't just a great success, it's also a pile of shite."

Love it or loathe it, few would deny it's remarkable – save Noble himself, whose flair for artistic provocation is matched only by his capacity for self-abasement. Which is where Kim Noble Will Die comes in – it's a portrait of the artist as suicidal depressive. The show doesn't so much blur the line between Noble's life and his art as carve it up with a razor blade. Watching it, you career from amusement, at what is surely a brilliantly realised piss-take, to horror, at what is surely a man with mental-health problems heralding his own self-annihilation from the stage.

It is – as a meeting with Noble confirms – more the latter than the former. Yes, Noble has a sense of humour. He is one half of Perrier Award-winning double act Noble and Silver, prankster fine-art graduates whose unique Situationist art-comedy won their Channel 4 series a Bafta nomination in 2002. But Noble also suffers from chronic manic depression, and had a breakdown in 2004. Much of his recent work has been in the mental-health sector, including an artist-in-residence stint at Homerton Hospital, and a video project with patients at south London's Maudsley NHS Trust. So there is nothing glib about Kim Noble Will Die. Its videos, which show Noble masturbating, self-harming and behaving oddly in supermarkets, document real events in his life. And the pact that Noble strikes with his audience is no laughing matter: in Edinburgh this year Noble stated that, unless audience members met him on George IV Bridge at 3am that night, he would kill himself – fortunately, some compassionate souls kept the appointment.

"When I first did the show," says Noble, "I was like, 'Yeah, I'm going to jump.' What a great performative spectacle that'll be." Would it? I'm not used to judging suicide according to its entertainment value. But Noble doesn't make the usual distinctions between his work and his personal pain. In the show, he plays the tape of a phone call in which he confronts his then-girlfriend with her infidelity. (She has threatened to sue over the use of her image in the show.) He laments – jokily, but painfully – the professional success of ex-colleagues Catherine Tate and Mathew (Gavin and Stacey) Horne. And he has upset his mum, by projecting her talking head on to the side of a bucket and having it say: "Kim is a fucking loser."

Most of us, forced to choose between art and our loved ones, would avoid exploiting or hurting those close to us. Not Noble. "I don't know why that side of me developed," he says. "I know it's really horrible for other people." He's sorry about that. But he has "a desire – not, not a desire, an instinct – if something hurts to go, whoosh" – and he makes a gesture of slicing straight to the heart of something – "to confront it, film it or do something with it. However it's hurting, try taking it somewhere else. Focus the energy of despair or madness somewhere else." And that process is worth hurting others for? "When you go a bit loopy," says Noble, "you don't give a shit."

The compulsion to record every aspect of his life, says Noble, was triggered by seeing the Danish film Festen, in which a son disrupts his father's 60th birthday party by branding him a child molester. (Noble's current show shares that movie's mix of cruelty and satire, of mischief alongside naive disgust at compromise and cover-up.) Back then, in the throes of a breakdown, "I had this urge to go into places, disrupt them and then video it. And I started being horrendous to my family and friends by following them with a camera, too." By the time he pulled out of depression, his professional partnership with Stuart Silver was disintegrating. "But Noble and Silver was what I did," says Noble. "I thought, 'What else do I do, now that's gone?'"

The answer was: keep filming himself. "I didn't know where I was going with it. But I was making videos, little bits and bobs, and I thought at some point I'd make them into a film, an exhibition or a live show." So, when Soho Theatre commissioned a performance for the Spill festival of live art in April, Noble turned to that autobiographical video archive. "When the material was put together, there was a narrative running through it," he says. "It all had an element of insanity and depression to it. An arc of death – which is a happy arc."

Together, the videos show Noble trying to lift himself out of gloom, by seeking meaning in life – or at least by leaving some legacy before his suicide. We see him buying self-help writer Paul McKenna's book Change Your Life in Seven Days – then taking 62 days to finish it. We see him naked in a bath, splattered in baked beans. Elsewhere, he removes products from shops, doctors them and replaces them. One such stunt involves doing something very unpleasant to a feminine hygiene product: one of several misogynist touches that led one reviewer to conclude, "Even for a show about going too far, he goes too far."

At points, watching Noble's show through my fingers, I wondered – when he ejaculates for the camera, gets pissed on – whether this wasn't just mental-health porn, an exercise in extremity one-upmanship. Both in London and Edinburgh, audience members reported the show to the police – "which was a bit strange," says Noble. "I wasn't expecting that kind of reaction." (That's naive too – Noble's show makes Richard Prince's Brooke Shields photos, recently impounded from the Tate, look demure by comparison.) One of the complainants, says Noble, "was a psychiatrist. He thought the theatre was being irresponsible for allowing me to do the show. He blamed the venue, which was quite nice. I was like, 'Yes, I've got away with it!'"

According to Noble, new material created for the show's revival (including footage of him getting arrested for stalking) is being discouraged by Soho Theatre for legal reasons. But Lisa Goldman, artistic director of the theatre, plays down its controversial nature, claiming that the April run received only one official complaint. She would rather focus on what she calls "a brilliant piece of work... brave and provocative". Yet, Goldman admits, "There were moments when I felt hostile to the show; to the self-obsession and narcissism, to the humiliation of himself and of other people." Is she referring to Noble hawking phials of his semen to women in the front row? Or perhaps the moment when the audience votes to evict one of its number from the theatre?

That is a characteristic masterstroke, which, by relocating a reality-TV convention to the live arena, exposes the callousness of 21st-century entertainment. But in his compulsion to record every detail of his life, and to present it warts-and-all rather than mediated into "art", Noble may be as much product of reality TV as its critic. He cautiously assents to that, but hopes there's more to his work than navel-gazing. "I really hope this show is more than just me masturbating for an hour," he says. "I hope that, because of how I operate, I can expose myself a little bit and that might ring true for other people."

And if that doesn't happen? Then "I am a twat and an egotist," says Noble glumly. That's why he's wary of endlessly reviving Kim Noble Will Die. "It feels strange to keep doing it. It's like, 'Why doesn't he just kill himself if he keeps going on about it?'" To Noble, a show about suicidal depression, performed by a man who's no longer depressed, would be a lie. "I felt it's going to be strange doing the show now, because things are working out for me at the moment," he says. "But in the past three weeks I just hit another one." A depression, he means. Which is bad – and good. "Because I'm happy to do the show again now. It feels right. I feel in that mood again."

'Kim Noble Will Die' is at Soho Theatre, London W1 (020 7478 0100, sohotheatre.com) from Tuesday to 9 January 2010