"Even in the wizarding world, hearing voices isn't a good sign", says Hermione Granger to Harry Potter, shortly after this scene, taken from the movie "Harry Potter and the Chamber of Secrets". I think it is easy to to agree with her. However, most things in life have two sides - and can be seen from both a positive and a negative side. In the case of Harry Potter, his hearing of voices meant that he got access into the mind of Lord Voldemort, and thus was able to understand and ultimately defeat him. And in the case of voices as the development of a mental disease, I think it is like with all diseases: disease symptoms are the natural consequence of you not seeing the more subtler signs of imbalance, which thus have become bigger, so that you more easily can notice them. In that way, disease signs can quite generally be thought of as more visible and helpful indicators of your state of being, which thus help you decide if these imbalances are things you want to keep, or if these imbalances are things you may want to choose to change. In the below TED talk, a girl who have heard real voices in her head gives a very insightful talk about how she got the symptoms, how they grew and became more severe, how she at last found people who helped her understand them for what they were, how she thus could start to listen to them in a more sound sense, and heal the underlying problems - until she now is completely free of the problematic symptoms, and even can beneficially help others. If you are interested in this phenomenon, or in the human mind in general, I can really recommend this video: its also only 14 minutes long.