Mental health by native-immigrant intermarriage in Sweden: a register-based retrospective cohort study.

Background: Native-immigrant intermarriage is often regarded as a proxy for integration, given that intermarried immigrants are more socioeconomically and culturally similar to natives than intramarried immigrants. This study aimed to assess whether integration affects mental health and care-seeking behaviours, examining prescription hazards for psychotropic medications by native-immigrant marital composition in Sweden.

Methods: Total population register data were used to identify first-time married couples residing in Sweden between 31 December 2005 and 31 December 2016. Index persons were distinguished by gender and partners' origin (native vs. immigrant), as well as by immigrants' regions of origin, with intramarried natives as references. Using Cox regression, hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated for antidepressant and anxiolytic prescriptions and adjusted for socioeconomic factors, presence of children and length and quality of marriage.

Results: Intramarried immigrant women had higher psychotropic prescription hazards than intramarried native references (HR 1.11, 95% CI 1.10-1.12), whereas intermarried immigrant women had equal hazards. Immigrant women's hazards were lower than native references after adjustment. Intramarried immigrant men had the greatest prescription hazards (HR 1.33, 95% CI 1.32-1.34), and intermarried immigrant men slightly higher hazards (HR 1.11, 95% CI 1.10-1.13), than intramarried natives. All were partly attenuated after adjustment. Intermarriage hazards increased by similarities in regions of origin, especially among men.

Conclusions: Integration indicated by intermarriage appears to be protective for the mental health of immigrants, especially for immigrant men. Future research should empirically disentangle the social, cultural and socioeconomic mechanisms underlying these health differences.