Refugee status and the incidence of affective psychotic disorders and non-psychotic bipolar disorder: A register-based cohort study of 1.3m people in Sweden

Refugees are at increased risk of non-affective psychotic disorders, but it is unclear whether this extends to affective psychotic disorders [APD] or non-psychotic bipolar disorder [NPB]. We conducted a nationwide cohort study in Sweden of all refugees, non-refugee migrants and the Swedish-born population, born 1 Jan 1984–31 Dec 2016. We followed participants from age 14 years until first ICD-10 diagnosis of APD or NPB. We fitted Cox proportional hazards models to estimate hazard ratios [HR] and 95 % confidence intervals [95%CI], adjusted for age, sex and family income. Models were additionally stratified by region-of-origin. We followed 1.3 million people for 15.1 million person-years, including 2428 new APD cases (rate: 16.0 per 100,000 person-years; 95%CI: 15.4–16.7) and 9425 NPB cases (rate: 63.8; 95%CI: 62.6–65.1). Rates of APD were higher in refugee (HRadjusted: 2.07; 95%CI: 1.55–2.78) and non-refugee migrants (HRadjusted: 1.40; 95%CI: 1.16–1.68), but lower for NPBs for refugee (HRadjusted: 0.24; 95%CI: 0.16–0.38) and non-refugee migrants (HRadjusted: 0.34; 95%CI: 0.28–0.41), compared with the Swedish-born. APD rates were elevated for both migrant groups from Asia and sub-Saharan Africa, but not other regions. Migrant groups from all regions-of-origin experienced lower rates of NPB. Income may have been on the causal pathway making adjustment inappropriate. Refugees experience elevated rates of APD compared with Swedish-born and non-refugee migrants, but lower rates of NPB. This specificity of excess risk warrants clinical and public health investment in appropriate psychosis care for these vulnerable populations. •Rates of affective psychotic disorders were 1.47 and 2.07 times higher for non-refugee and refugee migrants, respectively, than Swedes•After adjustment for income, rates remained 1.49 times higher amongst refugees•Migrant groups experienced lower rates of non-psychotic bipolar disorder than Swedes•Rates were elevated most in migrants from sub-Saharan Africa and refugees from Asia