Risk of psychotic disorders in migrants to Australia

Certain migrant groups are at an increased risk of psychotic disorders compared to the native-born population; however, research to date has mainly been conducted in Europe. Less is known about whether migrants to other countries, with different histories and patterns of migration, such as Australia, are at an increased risk for developing a psychotic disorder. We tested this for first-generation migrants in Melbourne, Victoria.

This study included all young people aged 15-24 years, residing in a geographically-defined catchment area of north western Melbourne who presented with a first episode of psychosis (FEP) to the Early Psychosis Prevention and Intervention Centre (EPPIC) between 1 January 2011 and 31 December 2016. Data pertaining to the at-risk population were obtained from the Australian 2011 Census and incidence rate ratios were calculated and adjusted for age, sex and social deprivation.

In total, 1220 young people presented with an FEP during the 6-year study period, of whom 24.5% were first-generation migrants. We found an increased risk for developing psychotic disorder in migrants from the following regions: Central and West Africa (adjusted incidence rate ratio [aIRR] = 3.53, 95% CI 1.58-7.92), Southern and Eastern Africa (aIRR = 3.06, 95% CI 1.99-4.70) and North Africa (aIRR = 5.03, 95% CI 3.26-7.76). Migrants from maritime South East Asia (aIRR = 0.39, 95% CI 0.23-0.65), China (aIRR = 0.25, 95% CI 0.13-0.48) and Southern Asia (aIRR = 0.44, 95% CI 0.26-0.76) had a decreased risk for developing a psychotic disorder.

This clear health inequality needs to be addressed by sufficient funding and accessible mental health services for more vulnerable groups. Further research is needed to determine why migrants have an increased risk for developing psychotic disorders.