Gender differences in Singaporean Chinese patients with schizophrenia

The purpose of this study was to compare gender differences in age of onset of illness, clinical features and prescription patterns in Chinese schizophrenia patients in Singapore. A cross-sectional study was conducted which recruited 903 subjects diagnosed with schizophrenia from the Institute of Mental Health between 2005 and 2008. Information on age of onset of schizophrenia, body mass index (BMI), psychiatric family history and current medication was collected via a standardised collection form. Symptom severity was assessed with Positive and Negative Syndrome Scale (PANSS). Differences in age of onset of schizophrenia illness, clinical features and prescription patterns were compared between gender groups. Among sporadic schizophrenia cases, female subjects demonstrated a bimodal distribution in age of onset of illness, and had a significantly later age of illness onset compared with male subjects. For subjects with family history of psychiatric disorder, no significant gender differences were found in age of onset of illness. Female subjects had significantly higher BMI, higher proportion of diabetes mellitus, lower negative symptom scores and were prescribed more atypical antipsychotics and antidepressants compared with male subjects. Male subjects after age 50 were prescribed a lower antipsychotic dose, but this difference was not observed in female subjects. In conclusion, we found differences in age of onset of schizophrenia, severity of negative symptoms and prescription patterns between the male and female gender groups in Chinese schizophrenia patients in Singapore. These differences were consistent with findings from Caucasian population, and could possibly be explained by influences of oestrogen.