Gender differences in schizophrenia in three cultures. Results of the WHO collaborative study on psychiatric disability.

As part of a systematic research project on the influence of gender factors on age at onset, symptomatology, and course of schizophrenia, data on gender differences in age at onset and symptomatology of schizophrenia from the WHO Collaborative Study "On Assessment and Reduction of Psychiatric Disability" were compared between seven research centres of three different cultural regions. Results on age at onset of five European centres confirmed the well known fact of an earlier onset in men. The earlier onset in women seen in Khartoum and Ankara could be attributed to patient selection because male/female differences in age at onset and male/female ratios in the various samples covary. In the Islamic centres no relevant gender differences in real age at onset and in symptomatology could be detected as probable causes of earlier hospitalisation of women. Major gender differences in symptomatology were found in the Balkan centres of Sofia and Zagreb with a high prevalence of delusional symptoms in women and depression in men. In Western Europe centres, nuclear schizophrenic symptoms were equally prevalent in either sex, while nonspecific symptoms like irritability and tiredness (more frequent in women) and maladaptive illness behaviours like alcohol abuse and social withdrawal (more frequent in men) differed between the sexes. Explanatory hypotheses and the implications of these results are discussed.