Project 466991

The risk of psychotic illness is more than two-times higher among certain migrant groups. In Ontario, risk is especially high among migrants from the Caribbean and refugees from Africa and South Asia. However, the causes of this heightened risk remain unclear. It has been proposed that exposure to social disadvantages across ones life can have cumulative effects that increase risk. One source of social disadvantage for migrants is being unable to speak the language of the new country. Prior research shows that differences between a migrants first language and the new language can influence their risk of psychosis, possibly by making the new language harder to learn. Women tend to learn languages more easily than men, which may impact the frequency of psychosis in each sex group. Marital status and education pre-migration may also have differing effects on how men and women learn language. Hence, this study examines how the association between language differences and psychosis may differ by sex among migrants to Ontario, and how sociodemographic and migration-related factors influence this relationship. We collected data from Immigration, Refugee and Citizenship Canada to identify migrants and their first languages. Languages will be classified by their similarity to English and estimated learning time. Health records will be used to identify cases of psychotic illness. Finally, we will calculate the risk of psychosis based on first language for men and women separately, and examine how the risk is affected by age at migration, country of origin, marital status at arrival, and highest level of education. This will identify sex-based factors that increase the risk of psychosis through effects on language learning, which will inform public mental health interventions.