MedicalResearch.com Interview with:
Anna-Clara Hollander PhD
Division of Social Medicine, Department of Public Health Sciences
Karolinska Institutet, Stockholm, Sweden.
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: The humanitarian crises in Europe, the Middle East, north Africa, and central Asia have led to more displaced people, asylum seekers, and refugees worldwide than at any time since the second world war. Refugees are known to be at an increased risk of mental health problems, such as post-traumatic stress disorder and other common mental disorders, compared to non-refugee migrants, but little is known about their risk of psychosis.
The aim of the study was to determine the risk of schizophrenia and other non-affective psychotic disorders among refugees, compared to non-refugee migrants, and the general Swedish population. We used a linked national register data to examine more than 1.3 million people in Sweden, and tracked diagnoses of non-affective psychotic disorders among the population. The cohort included people born to two Swedish-born parents, refugees, and non-refugee migrants from the four major refugee generating regions: the Middle East and north Africa, sub-Saharan Africa, Asia, Eastern Europe and Russia.
Results showed 3,704 cases of non-affective psychotic disorders during the 8.9 million person years of follow up. Refugees granted asylum were on average 66% more likely to develop schizophrenia or another non-affective psychotic disorder than non-refugee migrants. In addition, they were up to 3.6 times more likely to do so than the Swedish-born population. 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.
The increased rate in refugees was significant for all areas of origin except sub-Saharan Africa, for whom rates in both groups were similarly high relative to the Swedish-born population. One possible explanation is that a larger proportion of sub-Saharan Africa immigrants will have been exposed to deleterious psychosocial adversities before emigration, irrespective of refugee status. Alternatively post-migratory factors, such as discrimination, racism, and social exclusion may explain these high rates.
Overall, our findings are consistent with the hypothesis that increased risk of non-affective psychotic disorders among immigrants is due to a higher frequency of exposure to social adversity before migration, including the effects of war, violence, or persecution.
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