William Kurelek's The Maze (1969)
William Kurelek's The Maze is a documentary film about the life of celebrated Canadian artist William Kurelek, "dramatically told through his paintings and his on-camera revelations." The film documents the artist's struggles with attempted suicide and what he called a "spiritual crisis." At the center of the film is Kurelek's work The Maze, which he describes in the film as “a painting of the inside of [his] skull which [he] painted while in England as a patient in Maudsley and Netherne psychiatric hospitals.” This painting depicts a man’s "unraveled head lying in a wheat field. A curled up laboratory rat, representing his spirit, is trapped inside a maze of unhappy thoughts and memories."
More at Wikipedia.