Sex differences in pharmacotherapy of schizophrenia: findings from national survey 2012 on use of psychotropic medications

Objective To examine the sex differences in prescribing patterns of psychotropic drugs and drug-induced side effects in schizophrenia patients in China. Methods Using the same design and a standardized protocol as in 2002 and 2006, the cross-sectional survey was conducted from July to August, 2012 in 45 psychiatric hospitals/centers in 10 provinces and municipalities in China. Inpatients and outpatients with schizophrenia were consecutively screened for eligibility for this study. Sociodemographic characteristics and prescription pattern were collected by using a modified questionnaire for the study. Data comparisons between male and female were performed with univariate analysis. Multiple logistic regression analysis was employed to determine the gender differences in prescription pattern and drug-induced side effects. Results The sample consisted of 2 260 male and 1 979 female patients. Univariate analyses showed that male patients were younger than female patients (t=5.398), having an earlier age at onset (t= 5.662), higher percentage of being employed (χ2=31.597), and more negative symptoms (χ2=10.814) and aggressive behavior (χ 2=5.816), more likely to receive clozapine (23.9% (472/1 979 ) vs. 28.5% (645/2 260), χ2=11.955), higher antipsychotic doses (476 mg vs. 514 mg, F=14.003), less use of antidepressants (7.9% (156/1 979 ) vs. 6.0% (136/2 260) , χ 2=5.722) and benzodiazepines (23.9% (472/1 979) vs. 20.0%(451/2 260) , χ2=9.396), more frequent tardive dyskinesia (1.3%(25/1 979) vs. 2.1% (47/2 260) , χ2=4.212) and less weight gain (11.0%(218/1 979) vs. 7.7% (173/2 260) , χ2=14.233) and prolactin elevation (3.2% (63/1 979) vs. 1.7% (39/2 260) , χ2=9.548; all P<0.05). In multivariate analyses, greater rate of clozapine use (OR=1.268, P=0.001), less rate of benzodiazepines use (OR=0.841, P=0.025) and antidepressants (OR=0.78, P=0.045) , higher rate of tardive dyskinesia (OR=1.879, P=0.014) and less weight gain (OR=0.669, P=0.001) and prolactin elevation (OR=0.527, P=0.003) were independently associated with the male sex. Conclusion Gender is one of the independent contributors to psychotropic prescription pattern and side effects of antipsychotics in Chinese schizophrenia patients. Gender differences should be given more attention in research and clinical practice. Key words: Schizophrenia; Antipsychotic agents; Prescription; Gender; Survey