The incidence of admissions for schizophrenia and related psychoses in two cohorts: 1875–1924 and 1994–2010

Objective To investigate changes in incidence of admissions for schizophrenia and related non-affective psychoses in North Wales. Design Data from two epidemiologically complete cohorts of patients presenting for the first time to mental health services in North Wales between 1875-1924 and 1994-2010 are used in this study to map the incidence of hospital admissions for schizophrenia and non-affective psychoses. Setting The North Wales Asylum Denbigh (archived patient case notes) and the North West Wales District General Hospital psychiatric unit. Population 3168 patients admitted to the North Wales Asylum Denbigh between 1875 and 1924 and 355 patients admitted to the District General Hospital psychiatric unit between 1994 and 2010. Results There was an increasing admission incidence for schizophrenia between 1875 and 1900, a higher admission rate in the 1990s for men, followed by a drop in rates of admission for both genders since 2006. Admission incidences switch from parity between the sexes in the historical period to a doubling of the admission rates for men compared with women in the modern period. This admission pattern differs from the admission patterns for affective psychoses or organic disorders. Conclusion There have been changes in the incidence of admissions for schizophrenia in North Wales.