Effect of diagnostic criteria on the ratio of male to female schizophrenic patients.

Contrary to earlier epidemiological data, recent evidence points to a significantly greater proportion of men than women among schizophrenic patients diagnosed by current restrictive criteria. In this study, the authors analyzed the effect of using six different diagnostic systems (varying in their stringency) on the male to female ratio of schizophrenia among 387 inpatients. Diagnostic criteria representing a broad conceptualization of schizophrenia, such as the New Haven Schizophrenia Index, consistently yielded equal rates of schizophrenia among men and women. Those diagnostic systems representing more stringently defined schizophrenia, such as the Research Diagnostic Criteria, consistently yielded a male to female ratio significantly greater than the male to female ratio of the total sample.