Globally, suicide is the 15th leading cause of death, and the 2nd leading cause of death for young people based on a recent report by World Health Organisation (WHO). Common risk factors for suicide include adverse life experiences (e.g. trauma, abuse), psychiatric comorbidities, low socio-economic status, and unemployment (Andres & Halicioglu, 2010; Liu et al., 2014). Epidemiological data also show a variance among suicide risk by geographical location and region. A systematic review by Spallek et al. (2015) suggested a major heterogeneity in suicide risk among migrants in European countries. This could be explained by a variety of different factors, including the possibility of low levels of suicidality in the country of origin. It still remains unclear whether this heterogeneity can be attributed to the nature of migration, refugee status or time since immigration.

Refugees are a particularly vulnerable group, especially due to traumatic pre-, during and post-migration experiences (Steel et al., 2009). Research evidence has consistently suggested that the mental health needs of minority groups are often overlooked, following a stereotypical belief of universal ill health (Marshall et al., 2005; Melle et al., 2008) and barriers to accessing mental health services (Khan & Fafrm, 2017). The Office for National Statistics (ONS) in the UK recently published their annual suicide mortality figures, showing an increased suicide rate in the general population for the first time since 2013. This indicates the importance of public health research in investigating socioeconomic and health inequalities in potentially vulnerable populations, using well-validated instruments and providing methodologically rigorous and innovative interventions.

Hollander et al. (2019) used high-quality linked national Swedish registers to answer some key research questions in this area. Their study aimed to understand whether:

• refugees are at higher risk of suicide compared to non-refugee migrants,
• refugees are at lower suicide risk compared to the natives,
• increased time spent in the host country (Sweden) would increase the suicide risk among all migrant groups (the convergence hypothesis) and
• suicide risk varies by region of origin.

Methods

The authors developed a robust study design using a large longitudinal database of linked national registers, known as Psychiatry Sweden. These linked registers offer major research opportunities due to their richness and are considered to be reliable, well-recorded and high-quality (Ludvigsson et al., 2016).

A retrospective population-based cohort of 1,457,898 people born between 1 January 1975 and 31 December 1984 was established. These individuals were followed from their sixteenth birthday until the end of 2015, death or emigration.

The outcome variable for this study was death by suicide. This was defined using ICD-10 codes for suicide and death by undetermined intent.

The exposure variables for this study were:

• Migrant status
  • Natives who were born in Sweden to two Swedish-born parents
  • Refugees
  • Non-refugee migrants
• Time in Sweden in years: grouped to 0-5, 6-10, 11-15, 16-20, and 21-31 years post-migration.

All statistical models were adjusted a priori for age and gender. Additionally, the models were adjusted for region of origin (sub-Saharan Africa, Asia, Eastern Europe and Russia, the Middle East and North Africa) and individual disposable income. Cox regression models were conducted to estimate the suicide risk among sub-groups. In order to ensure the statistical power and validity of their findings, the authors ran three sensitivity analyses.

Results

The key findings were:

• There were no significant differences in the suicide risk between refugee and non-refugee migrants, and both groups had a lower risk of suicide than the Swedish-born population.
• There was no evidence that these patterns differed by region of origin in stratified analyses. Suicide risk varied by region of origin only when compared to the Swedish-born population and by gender. Men from all regions of origin except sub-Saharan Africa were at lower suicide risk than Swedish-born men. Women from Asia were also found to be at a lower risk than their native counterparts.
• During their first 5 years in Sweden no migrants died by suicide; however, after 21–31 years their suicide risk was equivalent to the Swedish-born population. After adjustment for income this risk was significantly lower for migrants than the Swedish-born population.

Conclusions

Although refugees are often faced with adverse life events and could be considered to be at a higher risk of suicide, the results from this study suggest otherwise.

This study highlights some key points, including the importance of acculturation and socioeconomic deprivation in changes in suicide risk over time. The authors state that the evidence:

strengthens the theory that suicide is strongly influenced by cultural factors that diminish over time and social adversity, because adjusting for disposable income attenuated the convergence.

Strengths and limitations

This study has many methodological strengths including:

• The researchers used a cohort of nearly 1.5 million people who were followed up for 32 years. The Swedish registers have been reported previously as well-recorded and reliable, while the data linkage offers a variety of research opportunities.

• Sweden is the primary high-income country offering asylum to a rising number of refugees and therefore registers offer a sufficient sample of people under the refugee status.

• The authors conducted several different types of sensitivity analyses to ensure the validity of their findings.

• This evidence adds to the literature and has the potential to inform both policy and future research, as they highlight the importance of acculturation.

Although this study follows a robust design, there are limitations. While the experience of trauma can be an important risk factor for suicide risk, in this study trauma was assumed. The national register used does not give the opportunity to explore participants’ experiences of trauma. Trauma is an important factor which should be considered in future studies, preferably not only experienced pre-migration but also during and post-migration.

Implications for practice

This paper is very important for public health, but why?

It’s 2019 and based on the latest UNHCR report:

• “Every minute in 2018, 25 people were forced to flee”
• “70.8 million forcibly displaced people worldwide as a result of persecution, conflict, violence, or human rights violations at end-2018”

It’s 2019 and based on the latest World Health Organisation report:

• “Close to 800 000 people die due to suicide every year”
• “One person dies every 40 seconds”
• “Suicide is the second leading cause of death among 15-29 year-olds globally”

As the authors point out:

Migration history could be an important aspect of history-taking in clinical settings, accompanied by an awareness that migration history may influence suicide risk for more than two decades in a country.

Migration is a key factor in people’s identity and has the power to influence mental health outcomes, both positively and negatively. This is relevant for international and forced migration, but also potentially intra-migration, e.g. from rural to urban areas. Although migrant health has been neglected as an area of research, steps are being taken to understand migrant and refugee mental health and resilience.

In order to learn more about the mental health of migrant and refugee populations, there must be a focus on other societal factors. These could include support networks, social cohesion, acculturation and environment. Understanding social determinants may be the path to understanding differing suicide risks in migrant and refugee populations compared to the general population.

Conflicts of interest

DK has collaborated in other research projects with the authors.

Links

Primary paper

Hollander, A., Pitman, A., Sjöqvist, H., Lewis, G., Magnusson, C., Kirkbride, J., & Dalman, C. Suicide risk among refugees compared with non-refugee migrants and the Swedish-born majority population. The British Journal Of Psychiatry 2019; 1-7. doi: 10.1192/bjp.2019.220

Other references

Andres AR, Halicioglu F. Determinants of suicides in Denmark: evidence from time series data. Health Policy 2010; 98(2–3): 263–9.

Liu RT, Miller I. Life events and suicidal ideation and behavior: a systematic review. Clin Psychol Rev 2014; 34(3): 181–92.

Saxena S, Krug EG, Chestnov O. Preventing Suicide: A Global Imperative. World Health Organization, 2014.

Spallek J, Reeske A, Norredam M, Nielsen SS, Lehnhardt J and Razum O. Suicide among immigrants in Europe–a systematic literature review. Eur J Public Health 2015; 25(1): 63–71.

Marshall, M., Lewis, S., Lockwood, A., Drake, R., Jones, P., & Croudace, T. Association between duration of untreated psychosis and outcome in cohorts of first-episode patients: a systematic review. Archives of general psychiatry 2005; 62(9), 975-983.

Melle, I., Larsen, T. K., Haahr, U., Friis, S., Johannesen, J. O., Opjordsmoen, S., … & McGlashan, T. Prevention of negative symptom psychopathologies in first-episode schizophrenia: two-year effects of reducing the duration of untreated psychosis. Archives of general psychiatry 2008; 65(6), 634-640.

Khan, F., & Amatya, B. Refugee health and rehabilitation: Challenges and response. Journal of rehabilitation medicine 2017; 49(5), 378-384.

Steel Z, Chey T, Silove D, Marnane C, Bryant RA and van Ommeren M. Association of torture and other potentially traumatic events with mental health outcomes among populations exposed to mass conflict and displacement: a systematic review and meta-analysis. JAMA 2009; 302(5): 537–49.

Ludvigsson JF, Almqvist C, Bonamy AK, Ljung R, Michaelsson K, Neovius M, et al. Registers of the Swedish total population and their use in medical research. Eur J Epidemiol 2016; 31(2): 125–36.

UNHCR (2018). Global trends: Forced displacement in 2018. United Nations High Commissioner for Refugees.

ONS (2018). Suicides in the UK: 2018 registrations. Office for National Statistics.

Photo credits

• Photo by Kevin Curtis on Unsplash
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