Male migrants living in cities are more likely to develop Schizophrenia - a disorder which has been shown to affect more men than women.
The mental illness is more variable than previously thought, according to a review into the incidence of schizophrenia, led by UQ Professor John McGrath.
It shows new cases of schizophrenia vary widely across the world ? affecting at least 40 percent more men than women, 400 percent more migrants than native citizens and is more common in cities than urban or rural areas.
The review involved analysis of more than 160 scientific articles, reports and theses on schizophrenia from around the world since 1960.
Professor McGrath, from the Division of Psychiatry is the Director of Epidemiology at the Queensland Centre for Mental Health Research.
Professor McGrath was this year awarded a Smithsonian Fellowship for research including investigating links between the season of a person's birth and their brain growth and development.
For the schizophrenia study, Professor McGrath and his team spent three years sifting through and translating data. He said the study was the first systematic review of new cases of schizophrenia and the results were "myth busters".
"Schizophrenia does vary across sites, sex, migrant status and urbanicity," Professor McGrath said.
"In the past, we have been lulled into a sense that schizophrenia does not vary. This was very misleading.
" He said some researchers had ignored the variation in the number of new cases believing the risk was the same in all places, within all groups.
He believed schizophrenia was more common in men than women possibly because boys' brains were more vulnerable to disorders during development.
"There is also some evidence that oestrogen may protect the brain," he said.
Professor McGrath said environmental factors such as infections, toxins, pollutants or lack of prenatal vitamin D, might explain the cases of schizophrenia in migrants and in cities.
More Information: www.qcsr.uq.edu.au