Expressionism

This was popular in Germany around the 1930s.

A European artistic faction in the first decades of the 20th century, prevalent in Germany (German Expressionism). Ranging from painting (e.g. Edward Munch) to literature (e.g. Gottfried Benn) to theatre (e.g. Georg Kaiser) and back ... The view on reality is coupled with the strong expression of the own feelings of the artist. For me, expressionism is defined mostly by the usage of sharp contrasts - language that is breaking with the rules of grammar and tends to be exclamatory (but also highly metaphorically), the usage of strong color differences in the paintings, and so on.

Other artistic factions in roughly the same timespace include dadaism, surrealism and futurism.

For example, in Eugene O'Neill's play, Emperor Jones, Jones is haunted by his fears, in particular feelings of subordination. O'Neill represents this by putting Jones on the block at a slave auction. The auction isn't "really happening," there in the middle of a jungle, but the script makes no indication that the auction is fantasy. In contrast, a realistic play would indicate the scene as a dream, a flashback, or some other dramatic convention with a defined break "in" and "out" of the play's action.

O'Neill was the first American playwright to use expressionism, and he claims to have been uninfluenced by the concurrent work in Germany in the 1920s.

A popular (though pretty much unconscious) misconception about expressionism is that it depends upon wacky colors, shapes, language, ideas, forms, etc to serve its function. Rather, an expressionistic work is freed from the conventions that force realism into nonwackyness. That's just my two cents.