Refugee migration and risk of schizophrenia and other non-affective psychoses: cohort study of 1.3 million people in Sweden

BMJ. 2016 Mar 15:352:i1030. doi: 10.1136/bmj.i1030.


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 χ(2) (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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Africa South of the Sahara / epidemiology
  • Age Distribution
  • Aged
  • Europe, Eastern / epidemiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Proportional Hazards Models
  • Psychotic Disorders / epidemiology
  • Psychotic Disorders / ethnology*
  • Refugees / psychology*
  • Refugees / statistics & numerical data*
  • Russia / epidemiology
  • Schizophrenia / epidemiology
  • Schizophrenia / ethnology*
  • Sex Distribution
  • Socioeconomic Factors
  • Sweden / epidemiology
  • Transients and Migrants / psychology*
  • Transients and Migrants / statistics & numerical data*