Sex differences in patients with schizophrenia: A prospective, multi-center study.

This study aimed to determine sex differences in socio-demographic and clinical characteristics of Chinese schizophrenia patients. In a multi-center, randomized, controlled, longitudinal study, 404 clinically stable patients with schizophrenia were randomly assigned to a maintenance group (optimal therapeutic doses continued throughout the study), a 26-week group (optimal therapeutic doses continued for 26 weeks, followed by a 50% dose reduction maintained until the end of the study), or a 4-week group (optimal therapeutic doses continued for 4 weeks, followed by a 50% dose reduction maintained until the end of the study). Participants were interviewed regularly using standardized assessment instruments, and followed up for 12-26 months. In the univariate analyses, the following factors were significantly associated with the male sex: not married, smoking, younger age, earlier age at onset, higher body mass index (BMI) at baseline, and more severe negative and hostility-excitement symptoms at baseline. The following factors were independently associated with the male sex in the multivariate analyses: not being married, smoking, a higher BMI at baseline, less deterioration in disorganized thoughts (4-week group) and positive symptoms (26-week group) and less increase in BMI in all three treatment groups over the study period. The majority of the sex differences in schizophrenia patients in this study are in accordance with results of previous studies worldwide suggesting that sex differences seen in schizophrenia are not dependent on cultural differences between geographically separate patients.