[Regional variations in the incidence of manic-depressive psychoses in the Danish psychiatric hospital system 1977-1993].

The aim of the present study was to investigate geographical variations in first ever admission rates for manic-depressive psychosis during the period 1977 to 1993 at a county level. The analyses were based on data obtained from the national Danish Psychiatric Case Register comprising inpatient contacts to Danish psychiatric hospitals and psychiatric units in general hospitals. The results showed that the national first ever admission rates for manic-depressive psychosis in the age-group 15-74 years declined by 44% from 25.3 per 100,000 in 1977-1979 to 14.2 per 100,000 in 1991-1993. For the older age-group the rates were slightly increasing. Comparison of the individual counties revealed significantly geographical variations with respect to incidence level and temporal trends over the years 1977-1993. The results may reflect local differences in the provision of outpatient services and primary care facilities. However, there is also the possibility that some patients might never be treated.