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

Betrayal is another theme in the story. Dion loses his sense of self at a young age when his best friend, Billy Brown, betrays him. He explains that when he was four, Billy "sneaked up behind when I was drawing a picture in the sand he couldn't draw and hit me ... and laughed when I cried." Consequently, his trust in his friend and humanity was shaken and, as he notes, "I became silent for life and designed a mask of the Bad Boy Pan in which to live and rebel against that other boy's God and protect myself from His cruelty."