Sex difference in comorbid depression in first-episode and drug-naïve patients with schizophrenia: Baseline results from the Depression in Schizophrenia in China study.

OBJECTIVE Comorbid depression is common in schizophrenia, and sex differences are prominent in many aspects of schizophrenia. However, few studies have investigated sex difference in comorbid depression in schizophrenia. This large sample study aimed to investigate sex differences in first-episode drug-naive (FEDN) patients with schizophrenia comorbid major depressive episode (MDE) (SZ-MDE). METHODS A total of 996 FEDN patients with schizophrenia (472 males/524 females) were recruited. The 17-item Hamilton Depression Rating Scale (HAMD-17) and Positive and Negative Syndrome Scale (PANSS) were applied. RESULTS There was no difference in the prevalence of comorbid MDE between male and female patients with schizophrenia. Among SZ-MDE patients, men had more severe psychotic symptoms (scores of PANSS total scale, negative scale, and general psychopathology scale), more severe depressive symptoms and higher proportion of severe depression than women (all p < 0.001). The early onset age of schizophrenia, smoking and PANSS positive score were the risk factors for comorbid MDE only in female patients with schizophrenia (all p < 0.05). Furthermore, in female patients with SZ-MDE, smoking was associated with the severity category of depression (p = 0.001, OR = 2.70). Multiple variable regression demonstrated HAMD17 score correlated with PANSS general psychopathology (p = 0.01) and total scores (p = 0.04) in female SZ-MDE. CONCLUSIONS Our results indicate sex differences in proportion of severe depression, clinical symptoms, and factors of comorbid MDE in FEDN patients with schizophrenia. These sex differences have clinical implications for the treatment of depression as related to the nature and severity of psychopathological symptoms in patients with schizophrenia.