What is the theme in The Great God Brown by Eugene O'Neill?

Identity is a theme in the story. In O'Neill's masterpiece, Long Day's Journey into Night, Mary Tyrone insists, "None of us can help the things life has done to us. They're done before you realize it, and... they make you do other things until at last everything comes between you and what you'd like to be, and you've lost your true self forever." Like Long Day's Journey into Night, The Great God Brown focuses on the search for identity and the devastating consequences for those who are unable to discover a true sense of self.