Migration history, minorities status and risk of psychosis: an epidemiological explanation and a psychopathological insight

Objectives A marked increased incidence of psychosis in migrants and ethnic minorities is a well established phenomenon. We aim to review data and insights arising from epidemiological and clinical/psychopathological studies regarding the relationship between migration history, minority status and risk of psychosis in order to evaluate the experiences of migrants and minority ethnic groups in host societies. Method A qualitative literature review was conducted to identify population surveys, services based studies, and clinical and biological studies on the relationship between migration and/or minority status and psychosis. Studies were identified by searching MEDLINE, PsychINFO and EMBASE. The search was supplemented by references provided by personal bibliographies of the investigators and by hand searching content pages of journals considered relevant to the topic. The search was run in June 2015. Results Risk differences related to minority groups vary in different countries. Socio-environmental risk factors faced by origin groups operate differently in the countries, depending on social experiences and available resources to cope with ad-versities. In addition, social factors can represent environmental risk factors because they might regulate gene expression. Facing severe or chronic social stress, such as isolation, low socio-economic status, late-life social adversities may result in long-term sometimes permanent alterations of the biological stress-response system, which can lead to the development of physical and mental illnesses. A number of studies have taken into account psychopathological and clinical features at psychosis onset and follow-up, and they do not support the suggestion that misdiagnosis can explain the high rates found in those populations. Conclusions Reviewed papers cover a period of more than 30 years and highlight that history of migration and minority status might both be important in increasing the risk of psychosis. Clinical studies reported that psychopathological differences and misdiagnosis cannot explain the excess of psychosis found in migrants and ethnic minorities. The excess of psychosis in migrant and ethnic minorities may be at least attenuated by several psychosocial interventions, targeted at social disadvantages and at most at-risk individuals and populations.