'There may be some people who kill themselves,' wrote Al Alvarez in The Savage God, his classic 1971 study of suicide, 'in order to achieve a calm and control they never find in life.' He went on to claim that for poet Sylvia Plath, a personal friend who'd committed suicide in 1963, it was a desperate way out of a corner she had boxed herself into. 

Sarah Kane by Aleks Sierz
'Actually, I see her more as a classical writer. Her work is connected with a form of theatre that is quite confrontational because it doesn't reassure you with social context or Freudian psychology - it doesn't explain things. It just presents you with these austere, extreme situations. She is the only contemporary writer who has that classical sensibility.'
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But 4.48 Psychosis inevitably raises troubling questions about the literature of despair. On the one hand, sceptics see Kane's work as a literal reflection of her life. The Telegraph's critic, Charles Spencer, wrote in May 1998 that 'you feel her work owes much more to clinical depression than to real artistic vision'. You could argue that her writing simply reproduces the fears and confusions of mental illness.

On the other hand, Kane's defenders - such as Graham Whybrow, the Royal Court's literary manager - emphasise her dramatic technique. Not only did she have a first-class honours degree in drama, but her work never stayed still. 'Each new play,' he says, 'was a new departure and to some extent an investigation of form. She left behind a body of work which is consistent in vision and diverse across a range of subjects.'
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Besides, what she admired most about Beckett was his sense of overcoming the darkness. When I talked to her, she emphasised that she was essentially interested in love and affection. 'I don't find my plays depressing or lacking in hope,' she said. 'To create something beautiful about despair, or out of a feeling of despair, is for me the most hopeful, life-affirming thing a person can do.'
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If, as Alvarez suggests, some people kill themselves to gain control and find calm, the irony is that Kane, who all her life struggled against being pigeonholed as a 'woman writer', is now powerless against being labelled a suicidal artist. And the problem with seeing Kane as an example of the Sylvia Plath syndrome - with her work refracted through the optic of her death - is that it reduces her art to biography, and limits its meaning.