Sex differences in the prevalence and clinical features of comorbid depressive symptoms in patients with never-treated, first-episode schizophrenia

Abstract

BackgroundMany aspects of schizophrenia are thought to be sex-specific, and patients with schizophrenia experience depressive symptoms at all disease phases. We investigated sex differences in patients with co-occurring schizophrenia and depressive symptoms, and investigated sex-specific relationships between depressive symptoms and clinical correlates. MethodsIn this cross-sectional study, we recruited Han Chinese inpatients (aged 16–45 years) in the Huilongguan mental hospital (Beijing, China) who had an acute, untreated first episode of schizophrenia that met the American Psychiatric Association's DSM-IV criteria for schizophrenia. Symptoms at the time of recruitment had to be moderate or severe according to the Clinical Global Impression Scale (≥4 points) and could not have lasted for more than 60 months. The Positive and Negative Syndrome Scale (PANSS) was used to assess clinical psychopathological symptoms and the 17-item Hamilton Depression Rating Scale (HDRS-17) for comorbid depressive symptoms. Pearson's χ2 test was used to calculate the incidence of co-occurring depressive symptoms in male and female patients. Odds ratios (ORs) were calculated using logistic regression comparing patients with and without depressive symptoms. The study was approved by the Insitutional Review Board of Huilongguan hospital and participants gave written informed consent before recruitment. FindingsBetween June 1, 2013, and Dec 20, 2015, 267 inpatients were recruited from consecutive admissions to the hospital. 27 were excluded because of documented medical abnormalities (n=7), substance dependence other than tobacco (n=5), other comorbid psychiatric disorders (n=6), or refusal or inability to provide consent (n=9). 240 patients (111 men and 129 women) were evaluable. Significantly more men (69 [62%]) than women (62 [48%]; χ2=4·28, p=0·039) had depressive symptoms (defined as total HDRS-17 score ≥8 points), which were also more severe (t=2·75, p=0·0058). Age, age at schizophrenia onset, and smoking were associated with significant sex differences for female patients, as were total, general psychopathology, negative PANSS symptoms, and cognitive factor subscale PANSS scores (all p<0·05). We found sex differences in the correlation between HDRS score and clinical phenotype, showing that in men, the PANSS general psychopathology subscore (β=0·75, t=7·72, p<0·0001) and the PANSS total score (β=0·44, t=4·81, p<0·0001) significantly predicted the HDRS-17 total score, whereas in women, the HDRS-17 total score was significantly predicted by the PANSS general psychopathology subscore (β=0·74, t=8·45, p<0·0001), the PANSS total score (β=0·47, t=5·71, p<0·0001), and the PANSS cognitive factor score (β=0·24, t=2·60, p=0·011). InterpretationOur results indicate that there are sex differences in the prevalence and severity of comorbid depressive symptoms, as well as their association with clinical correlates, in patients with never-treated, first-episode schizophrenia. Men had more severe depression, whereas disease in women was affected more by external factors. However, a cross-sectional deisgn could not establish definitive causative associations between sex and depressive or psychotic symptoms. FundingNational Natural Science Foundation of China (grant 81371477) and CAS Pioneer Hundred Talents Program.