How are voices generated?
"The truth is that we do not know why people hear voices or see visions. As the experience is so diverse, it’s likely that there are a number of different explanations. Whilst this can be frustrating for those who feel confused and would like a simple answer or some certainty, it means that the most important explanation is the one that the voice-hearer themselves finds useful. It is important not to impose your own belief on someone else’s experience – this is fundamental to the Hearing Voices Network approach. Rather than providing a dogmatic view of voice-hearing, we recognise and celebrate a festival of explanations."
See Why Do People Hear Voices? section on this page of Hearing Voices Network website (UK). Retrieved 11/24/13.