Differences in age of first hospitalization for schizophrenia among immigrants and nonimmigrants in a national case registry.

While previous studies have found an increased incidence of schizophrenia in some immigrant groups, differences in age of onset in these groups has not been examined. The purpose of this study was to compare age of first hospitalization of (1) native-born people versus immigrants, (2) immigrants from different countries of origin, and (3) first generation immigrants versus second generation immigrants; and to reexamine gender differences in age of first hospitalization. Data were extracted on all first hospital admissions nationally for the years 1978-1992 (n = 10,902) from the National Psychiatric Hospitalization Case Registry of the State of Israel Ministry of Health. Immigrants were older at time of first hospitalization than nonimmigrants, with considerable variations between different countries of origin. Second generation immigrants (i.e., born in Israel to immigrant parents) had ages of first hospitalization similar to people with native-born parents. Males had earlier ages at first hospitalization than females. The results suggest that immigration may have a delaying effect on age of first admission and support previous findings regarding gender difference in age of onset.