Language proficiency and mental disorders among migrants: A systematic review

In this review, we aimed to evaluate the association between language proficiency (LP) and the prevalence and severity of mental disorders in migrants. Secondarily, we aimed to consider whether sociodemographic and migration-related factors may affect the correlation between LP and mental disorders. MEDLINE, PsycArticles, EMBASE, and PsycInfo were systematically searched in April 2020 to identify original studies reporting prevalence of psychiatric symptoms or disorders among migrants and taking into account linguistic factors. The search of electronic databases initially yielded 1,944 citations. Of the 197 full texts assessed for eligibility, 41 studies were selected for inclusion in the systematic review. Thirty-five of the papers included reported a significant negative association between low LP and prevalence and/or severity of psychiatric symptoms or disorders, whereas only two records found the opposite relationship and four papers reported no association between them. Inadequate LP was consistently associated with several mental disorders in migrants, including psychotic, mood, anxiety, and post-traumatic stress disorders. Notably, all the four longitudinal studies that met inclusion criteria for this review reported a positive effect of LP acquisition over time on prevalence or symptom severity of mental disorders. Even though larger prospective studies are needed to better evaluate the relationship between LP and psychiatric disorders among migrants, we believe that the present findings could be inspiring for authorities to provide support and courses to improve migrants' language proficiency upon arrival.