[Possibilities of the epidemiologic method and various results of a population study of schizophrenia].

Some results of the epidemiological studies on schizophrenia conducted recently by the Epidemiology Department of the Psychiatry Institute, the USSR Academy of Medical Sciences, are summed up. The principal demographic data on schizophrenia, such as its prevalence and forms as well as the pathogenetic role of the sex and age are presented. Taking the paroxysmal forms as a model, the application of the epidemiological method in investigating the course and probable prognosis of schizophrenia is reviewed in greater detail. On the basis of the material from a representative group of patients with paroxysmal schizophrenia of the 15-year duration or over (1461 patients), the basic regularities of the time course of negative and positive disturbances during remission, as well as the specific features of the shift in the clinical forms of paroxysms are demonstrated. Statistical distribution shows that in most patients, the distinctive signs of a given form of the disease course tend to remain unaltered during the whole period of the illness. Apart from reflecting the stability of patterns of the disease course, these findings support the validity of the current schizophrenia differentiation.