OBJECTIVE:Bipolar disorder (BD) is frequently misdiagnosed as major depressive disorder (MDD), which may lead to inappropriate treatment and poor outcomes. This study aimed to examine prescribing patterns of antidepressants, antipsychotics and mood stabilizers in BD patients misdiagnosed with MDD in China. METHODS:A total of 1487 patients originally diagnosed with MDD were consecutively screened for diagnostic revision in 13 psychiatric hospitals or psychiatric units of general hospitals in China nationwide. The patients' sociodemographic and clinical characteristics were recorded using a standardized protocol and data collection procedure. The Mini International Neuropsychiatric Interview (MINI) was used to establish DSM-IV diagnoses. Data on psychotropic prescriptions were collected by a review of medical records. RESULTS:Three hundred and nine of the 1487 patients (20.8%) fulfilled DSM-IV criteria for BD; 118 (7.9%) for BD-I and 191 (12.8%) for BD-II on the MINI. Of the BD patients (n = 309), 227 (73.5%) received any use of antidepressants, 73 (23.6%) antipsychotics and 33 (10.7%) mood stabilizers. In multiple logistic regression analyses, compared with those with MDD, patients with BD-I were more likely to receive antidepressants (OR 1.7, 95% CI 1.1-2.8, p = 0.02), antipsychotics (OR 1.6, 95% CI 1.04-2.5, p = 0.04) and mood stabilizers (OR 3.9, 95% CI 2.1-7.2, p < 0.001), whereas patients with BD-II were more likely to receive mood stabilizers (OR 2.4, 95% CI 1.3-4.4, p = 0.003). There was no difference in the use of antidepressants (OR 1.1, 95% CI 0.8-1.5, p = 0.7) and antipsychotics (OR 1.3, 95% CI 0.9-1.9, p = 0.2) between BD-II and MDD. In addition, there was no difference between BD-I and BD-II in any use of antidepressants, antipsychotics and mood stabilizers. CONCLUSIONS:The prescription of antidepressants for BD patients misdiagnosed with MDD is very common, and only a very small proportion of patients received guideline-concordant treatment. Considering the potentially hazardous effects of inappropriate pharmacotherapy in this population, continuing education and training addressing the correct diagnosis of BD and rational use of psychotropic medications are needed in China.