Factors affecting time to rehospitalization for patients with major depressive disorder.

Major depressive disorder is a common psychiatric condition. Hospitalization is usually indicated for patients with more severe symptoms and severe functional impairment. Rehospitalization is known as the re-emergence of significant depressive symptoms. The purpose of the present study was to investigate the risk factors affecting time to rehospitalization. Rehospitalization status was monitored for all patients with major depressive disorder discharged from Kai-Suan Psychiatric Hospital between 1 January 2002 and 31 December 2003. Patients were followed up with respect to rehospitalization until 31 December 2004. The Kaplan-Meier method was used to calculate the median time to rehospitalization. Risk factors associated with rehospitalization were examined on Cox proportional hazards regression. Three hundred patients were recruited. Median time to readmission was 174 days (SD = 37). Comorbid alcohol abuse/dependence (hazard ratio [HR] = 1.841, 95% confidence interval [CI] = 1.229-2.758, P < 0.01), comorbid personality disorders (HR = 1.530, 95%CI = 1.053-2.223, P < 0.05), and the number of previous hospitalizations (HR = 1.121, 95%CI = 1.056-1.190, P < 0.001) were found to be predictors of the shorter time to rehospitalization over the 360-day study. Further research should be carried out to test risk factors in a prospective study, and to study the cost-effectiveness of interventions to reduce risk factors and rehospitalizations.