Prevalence and clinical severity of mood disorders among first-, second- and third-generation migrants

Background: The role of migration as a risk factor remains unknown for mood disorders because of poor data. We sought to examine the prevalence and severity of mood disorders (bipolar disorder (BD), unipolar depressive disorder (UDD) and dysthymia) in first, second, and third generation migrants in France. Methods: The Mental Health in the General Population survey interviewed 38,694 individuals. The prevalence of lifetime mood disorders, comorbidities, and clinical features was compared between migrants and non migrants and by generation. All analyses were adjusted for age, sex and level of education. Results: The prevalence of any lifetime mood disorder was higher in migrants compared with non-migrants (OR = 1.36, 95% CI [1.27 - 1.45]). This increased prevalence was significant for UDD (OR = 1.44, 95% CI [1.34 - 1.54]), but not for BD (OR = 1.15, 95% CI [0.96 - 1.36]) or dysthymia (OR = 1.09, 95% CI [0.94 - 1.27]), although the prevalence of BD was increased in the third generation (OR = 1.27, 95% CI [1.01 - 1.60]). Migrants with BD or UDD were more likely to display a comorbid psychotic disorder compared to non-migrants with BD or UDD. Cannabis-use disorders were more common in migrant groups for the 3 mood disorders, whereas alcohol-use disorders were higher in migrants with UDD. Posttraumatic stress disorder was more frequent among migrants with UDD. Limitations: The study used cross-sectional prevalence data and could be biased by differences in the course of disease according to migrant status. Moreover, this design does not allow causality conclusion or generalization of the main findings. Conclusion: Mood disorders are more common among migrants, especially UDD. Moreover, migrants with mood disorders presented with a more severe profile, with increased rates of psychotic and substance-use disorders.