Characteristics of unrecognised bipolar disorder in patients treated for major depressive disorder in China: general versus psychiatric hospitals.

ABSTRACT

OBJECTIVES: Bipolar disorder is often misdiagnosed as major depressive disorder. Such misdiagnosis partly depends on the type of treatment setting. This study compared general hospital psychiatric units with psychiatric hospitals in China with respect to basic demographic and clinical characteristics of patients with unrecognised bipolar disorder who are treated for major depressive disorder. METHODS: Patients treated for major depressive disorder were consecutively examined in 13 health centres (6 general hospital psychiatric units and 7 psychiatric hospitals) in China. Their socio-demographic and clinical features were recorded using a standardised protocol and data collection procedure. The DSM-IV diagnoses were established using the Mini-International Neuropsychiatric Interview. RESULTS: Of the 1487 patients included in the study, 309 (20.8%) were diagnosed with bipolar disorder. There was no significant difference between general hospital psychiatric units and psychiatric hospitals in the ratio of all types of unrecognised bipolar disorders (χ2 = 0.008, degrees of freedom = 1, p = 0.9) and bipolar II disorders (χ2 = 3.1, degrees of freedom = 1, p = 0.08). The proportions of unrecognised bipolar I disorders (χ2 = 4.1, degrees of freedom = 1, p = 0.04) differed significantly between the 2 types of study site. Multivariate analyses showed that patients with bipolar I disorders with more seasonal depressive episodes were more likely to receive treatment in general hospital psychiatric units (odds ratio = 3.3, 95% confidence interval = 1.1-9.8). CONCLUSION: Patients with bipolar I disorders receiving treatment in general hospital psychiatric units had different clinical characteristics compared to their counterparts treated in psychiatric hospitals in China.