Perceived discrimination and the risk of schizophrenia in ethnic minorities: a case-control study

Previous studies have reported a very high incidence of schizophrenia for immigrant ethnic groups in Western Europe. The explanation of these findings is unknown, but is likely to involve social stress inherent to the migrant condition. A previous study reported that the incidence of schizophrenia in ethnic groups was higher when these groups perceived more discrimination. We conducted a case-control study of first-episode schizophrenia, and investigated whether perceived discrimination at the individual level is a risk factor for schizophrenia.

Cases included all non-western immigrants who made first contact with a physician for a psychotic disorder in The Hague, the Netherlands, between October 2000 and July 2005, and received a diagnosis of a schizophrenia spectrum disorder (DSM IV: schizophrenia, schizophreniform disorder, schizoaffective disorder) (N = 100). Two matched control groups were recruited, one among immigrants who made contact with non-psychiatric secondary health care services (N = 100), and one among siblings of the cases (N = 63). Perceived discrimination in the year before illness onset was measured with structured interviews, assessing experiences of prejudice, racist insults or attacks, and perception of discrimination against one's ethnic group. Conditional logistic regression analyses were used to predict schizophrenia as a function of perceived discrimination.

Cases reported somewhat higher rates of perceived discrimination in the year prior to illness onset than their siblings and the general-hospital controls, but these differences were not statistically significant; 52% of the cases and 42% of both control groups had perceived any discrimination. Perceived discrimination at the individual level was not a risk factor for schizophrenia in these data. Perceived discrimination was positively correlated with cultural distance and cannabis use, and negatively with ethnic identity, self-esteem, and mastery.

The relationship between racial discrimination and psychosis may vary with the aspect of discrimination that is studied, and may also depend upon the social context in which discrimination takes place.