The association between immigrant subgroup and poor mental health: a population-based register study.

Ethnicity and immigrant subgroup (classified as refugee or nonrefugee) are associated with poor mental health among immigrants. The aim of this study was to assess whether national origin-based differences in poor mental health can be explained by immigrant subgroup and if its importance varies depending on origin. A cross-sectional, population-based study of Swedish residents was conducted in 2006. The outcome was poor mental health, measured with the proxy variable psychotropic drugs purchased. Explanatory variables included immigrant subgroup and origin. Potential confounders were age, marital status, education, time in Sweden, and children. Logistic regression was carried out. The total population was 5,507,262. Immigrants from countries outside the Organisation for Economic Co-operation and Development (OECD) numbered 298,641. Immigrant subgroup partly explained the higher likelihood of poor mental health among non-OECD immigrants; when each country or area was analyzed separately, most refugees had a higher likelihood than nonrefugees did. Immigrant subgroup partly explained the origin-based differences in mental health, but this varied between different groups of origin.