Hallucinations are a cardinal positive symptom of schizophrenia which deserves careful study in the hope it will give information about the pathophysiology of the disorder. We thought that many so-called hallucinations in schizophrenia are really illusions related to a real environmental stimulus. One approach to this hallucination problem is to consider the possibility of a demonic world. Demons are unseen creatures that are believed to exist in all major religions and have the power to possess humans and control their body. Demonic possession can manifest with a range of bizarre behaviors which could be interpreted as a number of different psychotic disorders with delusions and hallucinations. The hallucination in schizophrenia may therefore be an illusion—a false interpretation of a real sensory image formed by demons.
This was published in the Journal of Religion and Health, so you can trust it. Unless you think religion poisons everything.