Risk factors for voices in your head:

The Wilson Quarterly: Beyond the Brain by Tanya Marie Luhrmann: Epidemiologists have now homed in on a series of factors that increase the risk of developing schizophrenia, including being migrant, being male, living in an urban environment, and being born poor. One of the more disconcerting findings is that if you have dark skin, your risk of falling victim to schizophrenia increases as your neighborhood whitens. Your level of risk also rises if you were beaten, taunted, bullied, sexually abused, or neglected when you were a child. In fact, how badly a child is treated may predict how severe the case of an adult person with schizophrenia becomes—and particularly, whether the adult hears harsh, hallucinatory voices that comment or command.