Refugee status and affective disorders

Background

According to the UN Human High Commission for Refugees (UNHCR), there are 36 million refugees living outside of their country of origin, forced to leave as a result of persecution, conflict, violence, or human rights violations. This number has grown dramatically in the last 10 years due to ongoing conflicts and crises throughout the world.

In addition to the stressors that non-refugee migrants face when leaving their home and settling in a new country, refugees are likely to contend with even more challenges before, during, and after migration.

Previous research has shown that migrant populations are at increased risk of some mental health problems when compared to the native-born populations, including non-affective psychotic disorders (like schizophrenia) and affective psychotic disorders (like bipolar disorder or depression with psychotic symptoms), but lower rates of non-psychotic disorders (e.g. bipolar disorder without psychotic symptoms).

One of the potential explanations for higher rates of psychosis in migrant groups is due to higher rates of adverse experiences before, during, and after migration. Since refugees face a disproportionate burden of adverse experiences, it is possible that the rates of psychotic disorders may be even higher in refugee migrants compared to non-refugee migrants.

Why did we do this research?

The aim of this research was to explore if refugees were at a greater risk of affective psychotic disorders compared to non-refugee migrants and the native-born population. We also explored these patterns by region of origin to see if there were certain refugee groups most at risk of developing affective psychotic disorders.

What did we do?

We used data from the Swedish population registers, which includes all individuals living in Sweden, and collect information on age, sex, migration status, education, income, and health care. We included 1.3 million people born between 1984 and 1997.

Exposures: Refugee status & region We classified all participants by refugee status:

• refugee migrants,

• non-refugee migrants, or

• Swedish-born to two Swedish-born parents.

We also categorised all participants into 5 regions:

• Swedish-born,

• Asia & Oceania,

• Middle East and North Africa,

• Russia and Eastern Europe, or

• Sub-Saharan Africa

We excluded children of migrants (individuals with one or more migrant parents), and anyone without a residence permit (e.g. asylum-seekers do not receive a residence permit until a decision has been made on their asylum application. The registers also do not contain information on undocumented migrants or temporary visitors).

Psychiatric outcomes: We identified all cases of affective psychotic disorder and non-psychotic bipolar disorder, as recorded in the inpatient and outpatient electronic health records. We excluded anyone who had been diagnosed with non-affective psychotic disorder from this analysis.

Confounders: We adjusted for age and sex. We also considered income as a possible confounder in a sensitivity analysis.

Analysis: We calculated incidence rates for each population group, and used survival analysis to estimate unadjusted and adjusted hazard ratios.

What did we find?

The rate of affective psychotic disorder was 2.07 times higher in refugees compared to the Swedish-born population. The rate was 1.4 times higher in non-refugee migrants compared to the Swedish-born group.

When comparing refugee vs. non-refugee migrants, the rate of affective psychotic disorders was 1.48 times higher in refugees compared to their non-refugee counterparts.

Non-psychotic bipolar disorders: Rates of non-psychotic bipolar disorder were substantially lower in both refugee and non-refugee migrant groups compared with the Swedish-born group.

What does this mean?

We found that the rate of affective psychotic disorders was nearly twice as high in refugees compared to the native-born population, and further that there was nearly a 50% increase in rates when refugees were compared to non-refugee migrants.

We also found that refugees and non-refugee migrants had consistently lower rates of non-psychotic bipolar disorders.

These findings add to the growing body of literature showing the increased risk that refugees face of severe mental illness - that in addition to higher rates of PTSD and non-affective psychotic disorders, that refugees face a high burden of affective psychotic disorders. It is possible that experiences that refugees face during the migration and asylum-seeking process increase their risk of multiple mental health problems. The findings about lower rates of non-psychotic bipolar disorder are consistent with other studies, and require further exploration to see if these can be explained by differential help seeking and access to care.

In general, studies like this which highlight population groups most vulnerable to mental health problems can be essential to planning public health interventions and mental health care to ensure the most vulnerable groups have access to support. Additionally, research which reveals differences in patterns of diseases hints at possible mechanisms underlying these differences, which can further our understanding of the fundamental causes of mental health problems.

Read more

You can read the full paper here Journal of Affective Disorders

Behind the research

This analysis was led Lilian Burr as part of her MSC in the UCL Division of Psychiatry. She was supervised by Prof James Kirkbride and me.

This project would have not been possible without the ongoing support and collaboration with Dr Anna-Clara Hollander and Prof Christina Dalman at the Karolinska Institutet and the wonderful population-based registers collected and maintained by Statistics Sweden.