British Medical Journal
19 March 2016 (vol 352, issue 8049)
http://www.bmj.com/content/352/8049

.
Research Update
Refugee migration and risk of schizophrenia and other non-affective psychoses: cohort study of 1.3 million people in Sweden
BMJ 2016; 352 :i1030 (Published 15 March 2016)
Anna-Clara Hollander, postdoctoral researcher1, Henrik Dal, statistician2, Glyn Lewis, professor of psychiatric epidemiology3, Cecilia Magnusson, professor of public health epidemiology1 2, James B Kirkbride, Sir Henry Dale fellow3, Christina Dalman, professor of psychiatric epidemiology1 2
Abstract
Objective To determine whether refugees are at elevated risk of schizophrenia and other non-affective psychotic disorders, relative to non-refugee migrants from similar regions of origin and the Swedish-born population.
Design Cohort study of people living in Sweden, born after 1 January 1984 and followed from their 14th birthday or arrival in Sweden, if later, until diagnosis of a non-affective psychotic disorder, emigration, death, or 31 December 2011.
Setting Linked Swedish national register data.
Participants 1 347 790 people, including people born in Sweden to two Swedish-born parents (1 191 004; 88.4%), refugees (24 123; 1.8%), and non-refugee migrants (132 663; 9.8%) from four major refugee generating regions: the Middle East and north Africa, sub-Saharan Africa, Asia, and Eastern Europe and Russia.
Main outcome measures Cox regression analysis was used to estimate adjusted hazard ratios for non-affective psychotic disorders by refugee status and region of origin, controlling for age at risk, sex, disposable income, and population density.
Results 3704 cases of non-affective psychotic disorder were identified during 8.9 million person years of follow-up. The crude incidence rate was 38.5 (95% confidence interval 37.2 to 39.9) per 100 000 person years in the Swedish-born population, 80.4 (72.7 to 88.9) per 100 000 person years in non-refugee migrants, and 126.4 (103.1 to 154.8) per 100 000 person years in refugees. Refugees were at increased risk of psychosis compared with both the Swedish-born population (adjusted hazard ratio 2.9, 95% confidence interval 2.3 to 3.6) and non-refugee migrants (1.7, 1.3 to 2.1) after adjustment for confounders. The increased rate in refugees compared with non-refugee migrants was more pronounced in men (likelihood ratio test for interaction χ2 (df=2) z=13.5; P=0.001) and was present for refugees from all regions except sub-Saharan Africa. Both refugees and non-refugee migrants from sub-Saharan Africa had similarly high rates relative to the Swedish-born population.
Conclusions Refugees face an increased risk of schizophrenia and other non-affective psychotic disorders compared with non-refugee migrants from similar regions of origin and the native-born Swedish population. Clinicians and health service planners in refugee receiving countries should be aware of a raised risk of psychosis in addition to other mental and physical health inequalities experienced by refugees.

.

Editorials
Non-affective psychosis in refugees
BMJ 2016; 352 :i1279 (Published 15 March 2016)
Cornelius Katona, medical director
Risk is exacerbated by adverse experiences after arrival, including detention, unemployment, and racism
[Initial text]
In 2015, 244 million people (3.3% of the world’s population) lived outside their country of origin. This represents an increase of 39% since 2000.1 2 The decision to migrate may be made for economic betterment or (in the case of “refugees”) to escape war, persecution, or natural disaster. Such motives are not of course mutually exclusive. Substantial evidence shows that the risk of non-affective psychosis is increased (by a factor of about 2.5) in migrants compared with the indigenous population.3

In a linked paper (doi:10.1136/bmj.i1030), Hollander and colleagues argue that this increase is due predominantly to exposure to psychosocial adversities.4 They used national register data to carry out a cohort study of more than 1.3 million people in Sweden, in which risk of non-affective psychosis was compared not only between people born in Sweden and migrants to Sweden but also between refugees and non-refugees within the migrant group. They hypothesised that, because of their increased vulnerability to psychosocial adversity, incidence of non-affective psychosis would be particularly high in the refugee group. The study was restricted to relatively young people (born in 1984 or later). Follow-up was to the end of 2011 or to emigration, death, or a diagnosis of non-affective psychosis. The authors’ primary hypothesis was confirmed: incidence rates for non-affective psychosis were 385 per million in those born in Sweden, 804 per million in non-refugee migrants, and 1264 per million in refugees…