Age of migration and common mental disorders among migrants in early adulthood: a Norwegian registry study

Younger age of migration is associated with higher risk of psychotic disorders but the relationship between age of migration and common mental disorders is less clear. This study investigates the association between age of migration and diagnosed common mental disorders among migrants living in Norway. Using national Norwegian register data from 2008 to 2019, we compared the odds of a common mental disorder diagnosis in healthcare services during early adulthood among non-migrants, descendants and migrants with different ages of migration and lengths of stay. We also investigated differences in the relationship for different migrant groups and for men and women. Descendants and childhood migrants with ≥ 19 years in Norway had higher odds of common mental disorders than non-migrants, while those migrating during adolescence with ≥ 19 years in Norway had similar odds. Those migrating during emerging and early adulthood had lower odds. Overall among migrants, the relationship between age of migration and common mental disorders was more pronounced for migrants