Changes in the administrative incidence of schizophrenia.

First-admission rates to psychiatric hospitals, and data from certain psychiatric case registers suggest that there may have been a substantial decline in the administrative incidence of schizophrenia in recent years. However, data from the Nottingham case register show that rates for first-onset schizophrenia remained stable between 1975 and 1987. It is suggested that variations in trends between different parts of the UK may be partly explained by differences in the proportion of migrants and their children in the population at risk.