The role of gender in identifying subtypes of schizophrenia: a latent class analytic approach.

Past literature suggests that schizophrenic men and women may be at different risks for developing different subtypes of schizophrenia. This hypothesis was tested using data from the well-known retrospective cohort family studies, the Iowa 500 and the Iowa non-500. The sample consisted of 171 male and 161 female DSM-III schizophrenic patients and 713 of their first-degree relatives. First, bivariate tests for gender differences were conducted regarding family morbidity, age of onset, premorbid history, season of birth, and expression of deficit and affective symptoms. Restricted maximum likelihood latent class analysis was then used to test whether there was a subgroup of schizophrenic men who were more likely to have a low familial risk for schizophrenia or schizophrenia spectrum disorders, deficit symptoms, poor premorbid history, and birth in the winter months, suggesting possible early environmental insults, compared to schizophrenic women. Results showed that although men were more likely to meet these criteria, women also met them, thus suggesting gender differences in the prevalence of the subtype. Schizophrenic women were more likely to express a form of the illness characterized by dysphoria, persecutory delusions, and a higher family morbidity risk for schizophrenia than schizophrenic men. Results for spectrum disorders among relatives were equivocal with regard to gender.