Mary Barnes was an English artist and writer who suffered from schizophrenia but recovered to become a successful painter. She trained as a nurse and joined the army in World War II. She worked in Frankfurt for two years before returning to London as a full time nurse. In 1963, after reading R. D. Laing's book The Divided Self, she contacted him and began therapy, which intensified when she entered Kingsley Hall in 1965 and underwent regression therapy. During the process, she discovered a talent for art. She would later be described as "an ambassador for Laing", emerging from her journey to co-author a book about it with Joseph Berke, the resident psychiatrist who helped her. Her works, vivid oils often depicting religious themes, were first shown at the Camden Arts Centre in 1969. She subsequently became a respected artist, painting evocative works based on her experiences and showing her work on tour worldwide, accompanying it with talks on her experiences and mental health. In 1979 she cowrote Mary Barnes, a play following the story of her recovery, with David Edgar. This was broadcast on BBC radio in the United Kingdom, most recently in December 2011 on Radio 4 Extra.
In 1985, she moved to Scotland. Something Sacred, her book of conversations, writings and paintings, was published in 1989. In 1993, she moved to Tomintoul, where she died in 2001, aged 78.
In 2010 a major retrospective exhibition of Barnes's work opened at SPACE (studios) in London. She died in June 2001.