Contribution of long duration of undiagnosed bipolar disorder to high frequency of relapse: A naturalistic study in China

Background: With attention to misdiagnosis of bipolar disorder (BP), long duration of undiagnosed bipolar disorder (DUBP) had been reported recently in years. This study aims to investigate the contributions of long DUBP to the frequency of relapse in bipolar patients, and explore affect factors of DUBP. Method: From 26 hospitals throughout China, 3896 participants diagnosed with BP according to International Classification of Diseases 10th criteria were enrolled in this study. Socio-demographic and clinical data were collected from medical records and specific questionnaires through clinical interviews with patients and their relatives. Results: (1) Our results showed that the mean of DUBP was 40.52 months. In total, 779 patients (19.995%) reported DUBP greater than 5 years, and 1931 patients (49.564%) reported their DUBP greater than 2 years. The number of mood episodes was averaged 5.44, and the frequency ratio of (hypo) mania to depressive episodes was 1.49 (3.27/2.19). (2) Multiple linear regression analysis revealed that DUBP was significantly contributed to the number of relapse (Beta = 0.072, p < 0.001) after considering the confounding including gender, age at study entry, age of onset, age of first (hypo) manic episodes, age of first depressive episodes, type of first episodes and family history of mental illness. (3) Factors including age at the study entry (Beta = 0.526, p < 0.001), age of onset (Beta = 1.654, p < 0.001), age of first (hypo) manic episode (Beta = 0.348, p < 0.001), age of first depressive episode (Beta = 0.983, p < 0.001), depression as the type of first episode (Beta = 0.058, p < 0.001) and family history of mental illness (Beta = 0.029, p < 0.05) were significantly contributed to long DUBP. Conclusion: It was concluded that long DUBP might lead to high frequent relapse in bipolar patients. The factors correlated with long DUBP include older age, early age of onset, depression as the type of first episode and family history of mental illness. The findings of our study suggest emergency task to early reorganization of bipolar disorder, and improving clinicians' recognition of bipolar disorder from patients with depressive episodes, especially in children and adolescents. (C)2016 Elsevier Inc. All rights reserved."12th Five-year Plan" of National Key Technologies RD Program [2012BAI01B04]; Shanghai Clinical Center for Mental Disorders, National Key Clinical Disciplines at Shanghai Mental Health Center (OMA-MH) [2011873]; Program of Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine [2011-YJ-06]; Program of Health Department of Shanghai Municipal Government [20134071]; Shanghai Forensic Science Key Laboratory Program [KF1507]; National Natural Science Foundation of China [91232719]; Key Disciplines Program at Shanghai Jiaotong University School of Medicine [SJTUSM2008-6]SCI(E)PubMedSSCIARTICLEdrhongwu@126.com; zhangchen645@163.com; yirufang@aliyun.com77-817