I recently learned this bit of theatre jargon. Psychodrama obliterates the fourth wall, and at the same time totally makes the distinction between audience and stage.
The fourth wall is the imaginary “wall” at the front of the stage in a traditional three-walled box set in a proscenium theatre, through which the audience sees the action in the world of the play. The idea of the fourth wall was made explicit by Denis Diderot and spread in nineteenth century theatre with the advent of theatrical realism, which extended the idea to the imaginary boundary between any fictional work and its audience.
The presence of the fourth wall is an established convention of fiction and drama, which has led some artists to draw direct attention to it for dramatic or comedic effect. When this boundary is “broken”, for example by an actor onstage speaking to the audience directly, or doing the same through the camera in a film or television program, it is called “breaking the fourth wall.”