[Schizophrenia research using psychiatric case registries]

Almost 60 years after the establishment of the National Register of Psychoses in Norway psychiatric case registers have become an indispensable instrument of psychiatric research. By enabling a consecutive, person-related registration of contacts with the health care services of a geographically circumscribed region over long periods they have opened up new perspectives for epidemiological and followup studies and the evaluation of the care provided for schizophrenics. The severity of the illness and the fact that it frequently takes a long-term course are highly likely to lead to contacts with psychiatric services in areas with well-developed service structures. In this way case registers permit relatively reliable estimates of the treatment prevalence and first contacts, providing indicators of the true incidence. In the Federal Republic of Germany, however, as the only country in the world, cumulative psychiatric case registers have become illegal. An examination of long-term ecological, social and individual distribution processes among persons fallen ill with schizophrenia shows that the uneven distribution becomes effective even prior to the first onset. This is reflected in the marriage rates--the more so among males than females--, in the choice of occupation and the social chances of the schizophrenics to-be. In contrast, there is no reliable evidence for an increased risk of falling ill with schizophrenia after exposure to severe stress over a longer period of time. The age at first onset is some 10 years lower for males than females. Neither for this finding nor for the deviating birth season distribution, exhibited by approximately 10% of the schizophrenics, has any conclusive explanation been found. Even after the successful combat against tuberculosis falling ill with schizophrenia clearly reduces further life expectancy. The linkage of data from psychiatric case registers with twin, adoption and birth registers confirms the assumption that the probability of falling ill with schizophrenia is increased by genetic factors, thus refuting the alternative hypothesis of an environment-related transmission of the illness. Case registers are an indispensable means for the evaluation and cost analysis of the care provided for schizophrenics, above all in the establishment of new programmes of community-based complementary care for the chronically ill. Furthermore, they provide a solid basis for methodological studies on questions such as the stability of or transitions in the diagnosis over time.