MARY BARNES, who has died aged 78, was an artist, writer and poet whose account of her descent into and recovery from madness formed the subject of the 1979 play by David Edgar.

In 1965, Mary Barnes became the first resident of Kingsley Hall at Bromley-by-Bow, east London, an experimental therapeutic community opened by the radical Scottish psychotherapist R D Laing as a refuge for mentally ill people who were seeking an alternative to conventional psychiatric treatment.

Laing believed that a breakdown, if allowed to progress without medical intervention, could lead to a more stable state of mind. Thus Mary Barnes was encouraged to give in to, and regress to, a state of helpless infancy so that she could grow up again into sanity.

Early on in her treatment, she spent the days as a nurse at a hospital an hour away from Kingsley Hall, returning in the evenings to regress in her small room. But she soon gave up nursing to abandon herself entirely to her descent into madness.

She later recalled tearing off her clothes, smearing the walls with her faeces, being "wild and noisy about the house or sitting on a heap on the kitchen floor", half aware that she was losing her sanity. She soon refused to eat and had to be fed with a bottle, she squealed instead of speaking and slept naked in a wooden chest.

But with the help of her psychotherapist Dr Joseph Berke, who provided coloured crayons and encouraged her to paint with her fingers, Mary Barnes's spirit gradually returned. She took to painting fanatically, covering enormous canvasses with images from religion and nature, which were shown in exhibitions around the world.

She also began to write, describing experiences at Kingsley Hall in Mary Barnes: Two Accounts of a Journey Through Madness (1972), with Joseph Berke. The account formed the basis for the play Mary Barnes, by David Edgar, which was first performed at the Royal Court Theatre in London, with Patti Love as Mary Barnes, and Simon Callow as Dr Berke.

Mary Barnes was born on January 9 1923 at Portsmouth, where her father worked as a laboratory technician. She later described her parents as "abnormally nice" and blamed them for her depression.

Educated locally, she then trained as a nurse and served as a sister in the British Army in Egypt in 1946, and later as a nursing tutor. After entering a Carmelite convent, she converted to Roman Catholicism.

She began looking after mentally ill patients in a nursing home, but was then herself diagnosed a schizophrenic and told that she would probably spend most of her life in a mental institution. After undergoing electro-convulsive therapy and insulin treatment, she met R D Laing and entered Kingsley Hall.

In 1970, Kingsley Hall had to be returned to its trustees, and Mary Barnes returned to the outside world. Her artistic and literary success was such that other mentally ill patients were keen to undergo the same process, and, with Dr Berke, Mary Barnes set up the Arbours Housing Association, a charity which, provides homes as alternatives to mental hospitals.

Mary Barnes's other publications included Something Sacred (1989) with Ann Scott, a collection of poetry, paintings and reflections on mental illness and psychotherapy.

She lived for most of her life in Tomintoul, Banffshire, the highest village in the Highlands. Though wheelchair bound in recent years, Mary Barnes continued to paint, and travelled all over the world lecturing and exhibiting her works.