Incidence of psychotic disorders in immigrant groups to The Netherlands.

Background Previous reports on the incidence of schizophrenia in immigrant groups to The Netherlands were based on hospital data. Aims To compare the incidence of psychotic disorders in the immigrant groups to that in natives. Method Two-year first-contact incidence study in The Hague. Results The risks of schizophrenia, schizophreniform or schizoaffective disorder (DSM-IV criteria) were increased for subjects born in Morocco (gender and age-adjusted relative risk=4.5; 95% Cl 1.4-8.5), Surinam (relative risk=3.2; 1.8-5.7), The Netherlands Antilles (relative risk=2.9; 0.9-9.5) and other non-Western countries (relative risk=2.4; 1.3-4.7). This risk was also increased for Moroccans (relative risk=8.0; 2.6-24.5) and Surinamese (relative risk=5.5; 2.5-11.9) of the second generation. The risks for Turkish immigrants, first or second generation, and for immigrants from Western countries were not significantly increased. Conclusions This study indicates that the incidence of schizophrenia is increased in several, but not all, immigrant groups to The Netherlands. It is possible that factors associated with a process of rapid westernisation precipitate schizophrenia in people who are genetically at risk.