[Are sex differences in schizophrenia stable on a transnational basis?]

The ABC-Schizophrenia-Study (Häfner et al. 1991), investigating a large, representative sample of 267 first admissions, did not find any gender differences in the lifetime morbidity risk for this disorder or in the frequency of nuclear symptoms in male and female schizophrenic patients. Marked gender differences, however, could be detected regarding the age at onset and its distribution and regarding illness behavior and certain secondary symptoms. The transnational stability of these findings was tested with data from the WHO studies "On Assessment and Reduction of Psychiatric Disability" (including 510 patients from 7 centres) and on "Determinants of Outcome of Severe Mental Disorders" (with 1,292 patients from 11 centres). Studying pooled data sets from the studies minimized centre-specific selection effects on sampling. Major results of the ABC-Schizophrenia-Study were validated: the lack of a gender difference in the morbidity risk (cumulative lifetime incidence rates) for schizophrenia; lower mean age at first admission in males; an early, marked peak in the distribution of the age at onset in males; a later and broader peak in this distribution in females with a second peak after age 40-45; equal frequency of nuclear symptoms in both sexes; gender differences in some specific contents of delusions, secondary affective symptoms, social adjustment and illness behavior.