What is the theme in Norwegian Wood by Haruki Murakami?

Communication and mental illness are a theme in this book. Naoko's mental illness is bound up in an inability to communicate. She cannot express what she means, and she cannot talk about the things that are important to her. When Naoko is ill, she loses the ability to write. She becomes embroiled in her own mind, centered only on herself and her own problems and troubles. The isolation of the mind makes her withdrawn and self-centered, and it hurts both her and those around her. She is thrown into the "field well," where she is isolated and alone. Ultimately, it leads to death.