Substance use disorders in refugee and migrant groups in Sweden: A nationwide cohort study of 1.2 million people

Abstract

BackgroundRefugees are at higher risk of some psychiatric disorders, including post-traumatic stress disorder (PTSD) and psychosis, compared with other non-refugee migrants and the majority population. However, it is unclear whether this also applies to substance use disorders, which we investigated in a national register cohort study in Sweden. We also investigated whether risk varied by region of origin, age at migration, time in Sweden, and diagnosis of PTSD.Methods and findingsUsing linked Swedish register data, we followed a cohort born between 1984 and 1997 from their 14th birthday or arrival in Sweden, if later, until an International Classification of Diseases, 10th revision (ICD-10), diagnosis of substance use disorder (codes F10.X–19.X), emigration, death, or end of follow-up (31 December 2016). Refugee and non-refugee migrants were restricted to those from regions with at least 1,000 refugees in the Swedish registers. We used Cox proportional hazards regression to estimate unadjusted and adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) in refugee and non-refugee migrants, compared with Swedish-born individuals, for all substance use disorders (F10.X–19.X), alcohol use disorders (F10.X), cannabis use disorders (F12.X), and polydrug use disorders (F19.X). In adjusted analyses, we controlled for age, sex, birth year, family income, family employment status, population density, and PTSD diagnosis. Our sample of 1,241,901 participants included 17,783 (1.4%) refugee and 104,250 (8.4%) non-refugee migrants. Refugees' regions of origin were represented in proportions ranging from 6.0% (Eastern Europe and Russia) to 41.4% (Middle East and North Africa); proportions of non-refugee migrants' regions of origin ranged from 11.8% (sub-Saharan Africa) to 33.7% (Middle East and North Africa). These groups were more economically disadvantaged at cohort entry (p < 0.001) than the Swedish-born population. Refugee (aHR: 0.52; 95% CI 0.46–0.60) and non-refugee (aHR: 0.46; 95% CI 0.43–0.49) migrants had similarly lower rates of all substance use disorders compared with Swedish-born individuals (crude incidence: 290.2 cases per 100,000 person-years; 95% CI 287.3–293.1). Rates of substance use disorders in migrants converged to the Swedish-born rate over time, indicated by both earlier age at migration and longer time in Sweden. We observed similar patterns for alcohol and polydrug use disorders, separately, although differences in cannabis use were less marked; findings did not differ substantially by migrants’ region of origin. Finally, while a PTSD diagnosis was over 5 times more common in refugees than the Swedish-born population, it was more strongly associated with increased rates of substance use disorders in the Swedish-born population (aHR: 7.36; 95% CI 6.79–7.96) than non-refugee migrants (HR: 4.88; 95% CI 3.71–6.41; likelihood ratio test [LRT]: p = 0.01). The main limitations of our study were possible non-differential or differential under-ascertainment (by migrant status) of those only seen via pri...

Psychiatric care use among migrants to Sweden compared with Swedish-born residents: a longitudinal cohort study of 5 150 753 people

“…Low initial use of psychiatric care use across most migrant groups may indicate that these groups have lower overall rates of mental illness in recent migrants (PTSD and psychosis notwithstanding), and hence a lower need of psychiatric care (the ‘healthy migrant effect’). Our group has previously shown that immigrants to Sweden have lower rates of both substance use disorders and suicide, 29 30 for example, although rates converge to the Swedish baseline rate over time. This ‘healthy migrant effect’ may explain patterns of care use observed driven by labour migration, and associated with groups have previously demonstrated better general mental health.…”

Treatment Experiences with Norwegian Health Care among Immigrant Men Living with Co-Occurring Substance Use- and Mental Health Disorders

“…Further, research has documented that immigrant groups with SUD and MHD are at a high risk of neglect even in developed healthcare systems; possible reasons include lack of existing healthcare policies for these groups and insufficient funding to target specific areas of immigrants’ mental health care. 11 A recent Swedish cohort study reported increased rates of SUDs among immigrants who migrated at an early age or had lived for a long time in the host country 12 ; they were further disadvantaged by poor access to healthcare. 13,14 In addition, immigrants who have connections to a closely-knit drug scene or group may be hampered from seeking mental health treatment.…”

Addressing the context and consequences of substance use, misuse, and dependence: A global imperative

“…Although PLOS Medicine publishes research findings of general interest to the medical and public health communities, we received manuscript submissions describing research conducted in only a limited number of countries. In this Special Issue, the sole paper representing research conducted outside the US, Canada, and the UK is the report by Samantha Harris and colleagues [60], who analyzed Swedish register data from 1984–2016 to show that both refugee and nonrefugee migrants had lower rates of substance use disorders compared with Swedish-born individuals but that over time, the rates among migrants converged to that of Swedish-born individuals. The issue regrettably features no articles from Africa, Asia, or South America, and no articles focused on indigenous populations or on racial, ethnic, or sexual minority groups.…”