Assessing Mental Illness Risk among North Korean Refugees and Immigrants Resettled in South Korea

Importance: The global increase in the numbers of refugees and immigrants has made mental health a major public concern. Although they are divided, North and South Korea share a common ethnic heritage. Objective: To investigate mental illness risk among North Korean immigrants living in South Korea and compare it with that of the general South Korean population. Design, Setting, and Participants: This retrospective, population-based cohort study was based on National Health Insurance claims data from 2007 to 2019, and North Korean immigrants and refugees (NKIRs) and age-matched and sex-matched members of the general population (GP) were included with a 1:3 ratio. Data were analyzed from March 2022 to August 2022. Exposure: Emigration from North Korea to South Korea. Main Outcomes and Measures: Mental illness incidence and risk through a Cox proportional risk model adjusted for sex, age, disability, region, Charlson Comorbidity Index score, and insurance premium percentile. Results: A total of 37209 NKIRs and 111627 members of the GP were enrolled. The final analysis examined 112851 individuals (73238 [64.9%] female, median [IQR] age 34 [19-47] years), with 90235 (80.0%) in the GP and 22616 (20.0%) in the NKIR group. The propensity score-matching population numbered 24532 in total, with 12266 each in the NKIR and GP groups. NKIR patients had a higher mental illness risk than the GP (hazard ratio [HR], 2.12; 95% CI, 2.04-2.21). The multivariable adjusted HRs (95% CI) for developing mental disorders were 4.91 (3.59-6.71) for posttraumatic stress disorder, 3.10 (2.90-3.30) for major depressive disorder, 2.27 (2.11-2.44) for anxiety and panic disorder, 2.03 (1.58-2.60) for bipolar affective disorder, 1.85 (1.53-2.24) for alcohol use disorder, and 1.89 (1.46-2.45) for schizophrenia. Conclusions and Relevance: In this study, NKIR individuals showed a significantly higher risk of developing most mental disorders. Interventional strategies can prevent psychiatric morbidity and ensure adequate care for this population.