Background. The 1896 and 1996 populations of North West Wales are similar in number, ethnic and social mix and rurality, enabling a study of the comparative incidence and prevalence of service utilization over the course of a century.
Methods. We collected records on all psychiatric admissions from North-West Wales in 1894–1896 and 1996. These were assessed and diagnosed by the responsible sector area consultant.
Results. The data reveal substantially more patients admitted for all diagnoses in 1996, even when comparisons are restricted to detained patients. The incidence of hospitalization by detention for schizophrenia is slightly lower 1996 than in 1896 but the incidence of hospitalization is higher now than in 1996. The incidence of hospitalization by detention for non-affective disorder psychoses is the same in both 1896 and 1996 but there is a doubling of incidence of hospitalization. The incidence of hospitalization for bipolar disorders is similar in the two periods. Modern mental health services admit large numbers of personality disordered patients, where none were admitted 100 years ago.
Conclusions. Factors general to changing health care and expectations and others specific to mental health would appear to have led to the increase in rates of admissions observed in the modern period.