To compare the incidence of psychosis among migrants with the incidence among the native Dutch in Amsterdam, Gouda and Voorhout.
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.
We analyzed the Incidence Rate Ratios (IRR) of psychosis among various ethnic groups compared to the native Dutch using a Poisson model.
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.
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.

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