She struggled with intense manic depression for many years, but continued to work, and was for some time the writer-in-residence at the Royal Court theatre.
Whilst the Daily Mail described her first play as "this disgusting feast of filth", she is now acknowledged as a major force in British theatre, whose promising career was brought to a premature end by her suicide in 1999. Her last play, 4.48 Psychosis, was completed very shortly before she died and was performed a year after her death. In 2001, the Royal Court Theatre, which had staged premieres of all but one of her stage plays, procuced a season of her work. The critics were unanimous in their acclaim for the woman they had once scorned as reminding them of 'the naughtiest girl in the class'. Her influence on the next generation of writers remains to be seen, but it is already there in the plays of Debbie Tucker Green and in Caryl Churchill's Far Away (2000).