Migrant and ethnic minority status as risk indicators for schizophrenia: new findings.
Arguably, the strongest evidence of an environmental contribution to the cause of psychosis is the increased risk for certain groups of migrants and ethnic minorities. This article summarizes findings published since 2016. Two studies suggested that migration or minority status are proxies for exposure to an inferior social status. A study from Bologna, Italy, showed that the psychosis risk for internal migrants from Southern Italy was as much increased as that for international migrants. A report from New Zealand reported a higher risk for Maoris than for the remainder of the population.Furthermore, a Danish investigation showed that own-group ethnic density of the neighbourhood at age 15 strongly modified the psychosis risk at adult age. This rules out differential mobility during the prodromal phase as an explanation for the ethnic density effect. Preliminary evidence suggests that the psychotogenic effect of migration may be mediated by elevated dopamine in the striatum. An increasing body of evidence suggests that the higher psychosis risk for certain migrant or ethnic minority groups is due to an inferior social status. Neuroimaging of the dopamine system appears to be a promising avenue for research into pathogenesis.