Yet the truth is that we simply never know what makes some people take that final leap - or fall - into the hands of the "savage god". As Al Alvarez remarked in his book of that name, an unsurpassed account of literature and suicide, each suicide has "its own inner logic".
Whatever the reasons for Sarah Kane's own death - and they will surely be many, known and unknown - she joins a formidable list of artists and writers who have taken their lives this century: Virginia Woolf, who drowned herself in the Ouse; Paul Celan, who slipped into the Seine; Vladimir Mayakovsky, who put a pistol to his head; Kurt Cobain, who put a shotgun to his.
As Alvarez shows, the myth of the suffering artist is part of our cultural legacy, something which has been handed down to us at least since the Romantic poets. Our culture seems to have a need to romanticise both depression and creativity, and if the two come together, so much the better. Perhaps such romanticisation of suffering is easy, precisely because it appears as someone else's and not one's own. It seems easier to deal with the artist who is dead and fixed and graspable than with one who is living and whose work is unfinished. How differently our culture treats the work and person of Sylvia Plath, dead at 31, from that of her exact contemporary, Adrienne Rich, still working at 70; how differently we regard Mark Rothko, a suicide at 67, from his near-contemporary Richard Diebenkorn, who died from natural causes at 70. One might argue that Plath and Rothko are finer creative artists than Rich and Diebenkorn, but their suicides do nothing to prove the case one way or the other. The dead become objects of our analysis, a focus for feelings and attitudes that are really our own. The living can at least live their own lives, be the authors of their own stories.
But depression is only one path to creativity. The springs of artistic achievement are many - love, passion, joy, devotion, loss, longing, anger - all give rise to great and lasting work. Yet emotions in themselves do not produce anything. There has to be a talent and a craft and, above all, a drive, a need to produce.
Indeed, one might argue that depression is more commonly experienced by most of its sufferers as a serious inhibition of creativity, rather than as a spur to it. Depression is, after all, marked by a turning away from the world, into oneself: "the profoundly painful dejection, cessation of interest in the outside world, loss of the capacity to love, inhibition of all activity ... self-reproaches and self-revilings", as Freud described it in "Mourning and Melancholia" (1915). The philosopher Emmanuel Levinas wrote of "a weariness which is a weariness of everything and everyone, and above all a weariness of oneself"; existence is like a reminder of a commitment to exist, "with all the seriousness and harshness of an unrevokable contract". Citing the philosopher William James, he says weariness "lies between the clear duty of getting up and the putting of the foot down off the bed".
As a psychotherapist, I see this every day in my practice. People are imprisoned in and by their condition, as weighed down as the figure in Durer's Melancholia, unable to achieve or even contemplate any but the most commonplace act. Hopefully, there comes a time when they begin to move out of this straitjacket. But any creative endeavour, whether painting, writing, sculpture or music, is both a sign of recovery and an aid to it, but only once one has left the darkness visible behind. You cannot create your way out of it.
For the artist, the creative work often follows an escape from depression. Toni Morrison has written of how she wrote her first novel The Bluest Eye after such a period, and Philip Roth's greatest novel, American Pastoral, followed a period of serious suffering. Depression transcended may allow the creative artist to speak for him or her self, but also for and to something universal. It is this, of course, which gives art some of its greatness, its ability to articulate for the many.
And yet, the myth persists - death, darkness and greatness, inextricably entwined. One thinks of the paintings of Mark Rothko, who worked until the day of his death, 29 years ago to the week that Sarah Kane died, or the poems of the American John Berryman, or the songs of Nick Drake. There is an equally potent myth around the destructive and self-destructive behaviour short of suicide - alcoholism, drug abuse and so on - of so many artists and musicians But let us think, then, of the artists who survive and who, if not actually happy (whatever that might mean), do not seem much less content than the rest of us - Joyce, Eliot, Beckett, Henry Moore, Seamus Heaney.
The matter cannot, of course, be sorted out by any crude scoring - depressives, 43, non-depressives, 25 - or the other way around. There are different degrees of and kinds of depression - a continuum from what the novelist William Styron calls the "manageable doldrums" to an "anxiety, agitation and unfocused dread" that escapes description. One suspects that most creative work worthy of anything emerges mainly from the less severe end of the spectrum. Yet it has to be acknowledged that artists such as Rothko, Plath, Berryman, Celan and Levi were working right up to the point of their deaths. Whether their depressions fuelled or finally killed them, their work, their creativity, could not save them.
One wonders whether a different path might have rescued them. In an age in which the individual is sovereign, it is often assumed that self- expression has to be a good thing in times of difficulty. But what if particular kinds of self-expression take one deeper into the abyss? The palpable despair, say, of the last poems of Paul Celan or the final paintings of Mark Rothko must certainly reflect the state of their being in the world at the time. But it can equally have taken them further into that darkness from which there was no way out.
One thinks here of the Spanish writer Jorge Semprun, who took a completely different road. Released from Buchenwald in 1945, Semprun was advised by many to "write it all down", to tell his - and other people's - story, and he was on the point of doing so. In 1946, however, he took a decision - actually, he says a "decision took" - to pursue life rather than literature. That, he felt, was the stark choice in front of him. In his case, the life was that of political activity (at first for the underground Spanish Communist Party) and although he did write in the meantime, his masterwork, Literature or Life (Viking, 1997), was not published until nearly 50 years after the camp gates were opened. In an epiphanous moment, in a house in Locarno, a young woman's head on his shoulder, Semprun thought: "Life was still liveable. It was enough to forget, and to decide this with brutal determination. The choice was simple: literature or life. Would I have the courage - the cruelty toward myself - to pay the price?"
So perhaps we should be a little suspicious of that "Oh yes" response so common to many of us when we hear of the death of a talented person, a sigh of inner confirmation as though somehow it was simply to be expected, an event waiting to take place. Only those who knew Sarah Kane personally can mourn her. Perhaps the rest of us could be less in thrall to the romantic ideas to which her death is prey and think more of the thousands of "nameless" suicides whose deaths each year shame us, as individuals and as a society.
Paul Gordon is the author of `Face to Face: Therapy as Ethics' (Constable, pounds 15.99).