[The incidence of psychotic disorders among migrants in the Netherlands: findings from the multinational EU-GEI study]

Abstract

Objective: To compare the incidence of psychosis among migrants with the incidence among the native Dutch in Amsterdam, Gouda and Voorhout.

Design: We identified patients with a first treated episode of psychosis (ICD-10 codes F20-F33) in 2010-2013 as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. Information on the composition of the population made it possible to calculate incidence rates.

Method: We analyzed the Incidence Rate Ratios (IRR) of psychosis among various ethnic groups compared to the native Dutch using a Poisson model.

Results: The standardized rates in Amsterdam were 55.3/ 100,000 person-years (py) for migrants and 24.9/ 100,000py for native Dutch. In Gouda and Voorhout, these rates were 28.5 en 20.0/ 100,000py. We found increased rates among Moroccan males of the first (IRR=4.07 [95%-CI: 1.76-9.42]) and second generation (IRR=6.48 [3.30-12.68]) in Amsterdam. In Gouda and Voorhout, we found increased rates both among Moroccan males (IRR=3.37 [1.17-9.74]) of the first generation and Moroccan females of the second generation (IRR=7.10 [2.79-18.06]). High rates were also found in Amsterdam for male migrants from Eastern Europe (IRR=4.52 [2.24-9.11]), migrants from sub-Saharan Africa (IRR=3.15 [1.68-5.91]) and first-generation migrants, both males and females, from Surinam and the Netherlands Antilles. We found a decreased incidence for Western migrants.

Conclusion: We found an increased incidence of psychosis among non-Western migrants and in Amsterdam also among Eastern-European migrants. The variation by region of origin and destination generation, and gender suggests that this risk is strongly influenced by the societal context.