First contact incidence of psychotic disorders among native Dutch and Moroccan immigrants in the Netherlands: influence of diagnostic bias.

Abstract Background Several studies have reported increased incidence rates of psychotic disorders among immigrant groups. Surprisingly, the cross-cultural validity of the diagnostic instruments that were used was never tested. Aims To examine whether the incidence rates of psychotic disorders including schizophrenia among Moroccan immigrants to the Netherlands remain increased when a cultural sensitive diagnostic interview is used. Method We compared first contact incidence with a standard and a cultural sensitive version of a diagnostic interview. Results Age and gender adjusted relative risk for psychotic disorders and schizophrenia among Moroccans compared to native Dutch was 7.9 (95% CI 4.7–13.5) and 7.8 (95% CI 4.0–15.2) respectively based on the standard diagnostic interview and 4.2 (95% CI 2.3–7.9) and 1.5 (0.5–4.3) respectively based on the cultural sensitive version the diagnostic interview. Conclusion First contact incidence of schizophrenia among Moroccans was no longer significantly higher than among ethnic Dutch people when a cultural sensitive diagnostic procedure was applied.