Association between the high-dose use of benzodiazepines and rehospitalization in patients with schizophrenia: a 2-year naturalistic study

BACKGROUND High-dose use of benzodiazepines (BZPs) reportedly causes adverse effects on cognitive function and quality of life in patients with schizophrenia. However, effects of BZPs on the clinical course of schizophrenia have not been clarified. This study was set out to investigate the association between BZPs and rehospitalization of patients with schizophrenia. METHODS In this retrospective study, patients with schizophrenia who were discharged from Tokyo Medical University Hospital between January 2009 and February 2012 were eligible as subjects. One hundred and eight patients who continued treatment for >2 years after hospital discharge were included in this study. Clinical characteristics, doses of prescribed medication such as BZPs and antipsychotics, and Global Assessment of Functioning scores at discharge were investigated. The primary outcome was rehospitalization of patients for any reason. RESULTS In a total of 108 subjects with schizophrenia, 44 subjects (40.7%) experienced rehospitalization during the 2-year study period. A multivariate analysis by the Cox proportional hazards model revealed that low educational history (hazard ratio =2.43, P=0.032), younger onset age of schizophrenia (hazard ratio =2.10, P=0.021), and higher diazepam-equivalent dose (hazard ratio =6.53, P=0.011) were significantly associated with the time to rehospitalization after hospital discharge. CONCLUSION The results of this study suggest that high-dose use of BZPs at discharge in patients with schizophrenia might be associated with a shorter time to rehospitalization.