Certain immigrants have a higher risk of developing a psychotic disorder, according to a recent study.

Compared to the general population of Ontario, Canada, immigrants from the Caribbean and Bermuda, as well as refugees from East Africa and South Asia, have a 1.5 to 2 times higher risk of psychotic disorders, according to researchers at the Institute for Clinical Evaluative Sciences (ICES) and the Centre for Addiction and Mental Health (CAMH).

Nearly 30 percent of Ontario's population is a first generation migrant. This makes the province homes to the largest number of migrants in Canada, CTV News reported.

"We found that refugees had about a 25 per cent greater risk of psychotic disorders compared to immigrants. We also found that neighborhood-level income acted as a protective factor, with migrants who were living in the wealthiest neighborhoods in the province having half the risk of psychotic disorders compared to migrants living in the poorest neighborhoods in the province," Kelly Anderson, lead author and post-doctoral research fellow at ICES Western, said in a statement.

For the study, researchers reviewed the medical records of nearly 4 million people between the 14 and 40 years of age,Healio reported.

They found that the incidence rate of psychotic disorder was 55.6 per 100,000 person years among the general population, 51.7 per 100,000 person years among immigrants, and 72.8 per 100,000 person years among refugees.

"The patterns we observe suggest that psychosocial factors associated with the migratory experience and integration into Canada may contribute to the risk of psychotic disorders," Dr. Paul Kurdyak, senior author of the study, said in a statement.

The findings are detailed in CMAJ Open.