At some point in their lives, about 5 percent of people hear voices or see things that others cannot perceive.
The study suggests hallucinations and delusions are more common than previously thought in the general population. Involving more than 31,000 people from 19 countries, it was the most comprehensive ever completed, says Professor John McGrath of the University of Queensland.
“We used to think that only people with psychosis heard voices or had delusions, but now we know that otherwise healthy, high-functioning people also report these experiences,” says McGrath, a researcher at the Queensland Brain Institute.
“Of those who have these experiences, a third only have them once and another third only have two-to-five episodes across their life. These people seem to function reasonably well.
“So it’s incredibly interesting that not only is hearing voices more common than previously thought, but it’s not always linked to serious mental illness.”
Why some people recover
The study was a population-based survey that involved approaching randomly selected members of the community, sitting down with them, and conducting a very detailed interview about their mental health.
“These people were representative of the general population, not seeking mental health assistance,” says McGrath.
The study finds that auditory hallucinations are more common in women than men, and they are also more common in people from wealthier countries.
McGrath says the findings could help generate new research into the causes of these isolated symptoms. “In particular, we are interested in learning why some people recover, while others may progress to more serious disorders such as schizophrenia,” he says.
“We need to understand why it’s temporary for some people and permanent for others. We can use these findings to start identifying whether the mechanisms causing these hallucinations are the same or different in both situations.”
When to seek help
“We need to rethink the link between hearing voices and mental health—it’s more subtle than previously thought,” he adds.
“While people may experience a false perception such as mistakenly hearing their name called out in public, hallucinations and delusions are quite detailed, for example, hearing voices that no one else can hear or a belief that somebody else has taken over your mind.
“People should be reassured that there isn’t anything necessarily wrong with them if it happens once or twice, but if people are having regular experiences we recommend that they seek help.”
The study appears in JAMA Psychiatry, and received funding from the National Health and Medical Research Council.
Source: University of Queensland