The contribution of European case registers to research on schizophrenia.

Psychiatric case registers have become important instruments for epidemiological research and for the evaluation of care provided for persons suffering from schizophrenia. Under the condition of a sufficient provision of care, case registers permit relatively reliable estimates of "treated" incidence and prevalence, and enable the investigation of associations between morbidity risks, disease courses, and variables such as ecological, social, and occupational factors. The linkage with twin, adoption, and birth registers provides new opportunities for the investigation of the impact of genetic versus environmental factors on the probability of becoming ill with schizophrenia. On the basis of long-term utilization figures, case registers enable a valid measure for controlling utilization, effectiveness, quality, and costs of care. Because case registers take demographic and regional factors into account, they enable better planning of mental health services--a task that grows more important with the shift from hospital-based to community-based treatment, especially for the chronic patients.