Western medicine typically views anyone who admits to being told what to do by disembodied voices as suffering from psychosis. But that is not the case everywhere – so what can we learn from those who treat these hallucinations differently?

Hearing voices is more common than you might think. Studies through the decades have shown that a surprising number of people without any previously diagnosed mental health condition – often more than three quarters of those taking part – experience voices speaking to them from an unknown source.

In Western psychiatry, however, these auditory hallucinations are one of the principal symptoms of psychotic disorders. And the resulting stigma surrounding these mental health conditions means that few people will publicly admit to hearing voices in their head.

But in some cultures these hallucinations are not only widely accepted but actively celebrated. They are seen as offering guidance or as helping to keep people safe. What can we learn about mental health from other cultures? And can we see people who experience hearing voices in a different light?

Local expectations shaped by the culture, environment and people we grow up with affect whether those who experience hallucinations are judged to be ill, or not, says Tanya Luhrmann, a professor of anthropology from Stanford University in the US, and co-author of the book Our Most Troubling Madness.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-5), which is the standard reference for diagnosing mental disorders in the US, lists hearing voices as a primary feature of schizophrenia and psychosis. Yet in Western countries some hallucinations are more accepted than others – as many as 80% of bereaved Americans and Europeans report seeing, hearing or feeling a close relative who has passed away. The Achuar tribes of Ecuador, by comparison, prohibit mourning the loss of family members because they consider visions or dreams of the deceased as threatening to the souls of the living.

Even drug-induced hallucinations of voices vary depending on cultural differences. In the Amazon, the Siona tribe believe that such hallucinations are an experience of an alternative reality, while the Schuar tribe believe that everyday life is an illusion, and reality is what is seen during a hallucination.

People's personal responses to hearing a voice in their head can also be shaped by culture. A comparison between US, Ghanaian and southern Indian psychosis patients found that Americans were more likely to hate their internal voice, and usually did not know the identity of the speaker. Patients in Chennai in India and Accra in Ghana, by comparison, associated their internal voices with God or family members, and did not always dislike hearing them, according to the study conducted by Luhrmann.

More than half of the people from Chennai in the study said that they heard the voices of specific family members, such as their parents, mother-in-law or sisters. These voices offered practical advice, instructions for daily tasks, and were also there to give a telling off. The voices told the interviewees to go to the shops, to prepare food and to bathe. "They talk as older people advising younger people," said one interviewee. "It teaches me what I don't know," said another.

For the participants in Chennai, the voices seemingly had a more realistic quality, and only a small number of interviewees said that they did not recognise the voice that spoke to them. Some of the interviewees from Accra went further and said that their voices were positive influences. One man told Luhrmann, "They just tell me to do the right thing. If I hadn't had these voices I would have been dead long ago". However, Americans were more likely to describe their voices as imaginary. "I don't think there's anything there or anything. I think it's just the way my mind works," one US participant said to Luhrmann.

Some of the Chennai interviewees spoke of........

© BBC