AUTHOR=Wang Zhonggang , Cao Yuying , Zhu Yaya , Li Kunkun , Jiang Xianfei , Zhuo Chuanjun , Triplett Patrick , Li Jie 

TITLE=Differences in Demographic and Clinical Characteristics of Patients With Depressive vs. Manic First Episode of Bipolar Disorder

JOURNAL=Frontiers in Psychiatry

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2021.616415

DOI=10.3389/fpsyt.2021.616415

ISSN=1664-0640

ABSTRACT=Background: Bipolar patients may present with different symptoms at first onset. The aims of this study are to assess for differences in demographic or clinical variables based on a patient’s index episode of bipolar disorder and on risk of recurrence over a two-year period. 
Methods: 742 patients with bipolar disorder in China was analyzed. Patients were divided into two groups according to their index episode of bipolar disorder, either depression or mania. Patients in mixed state first episode were classified based on predominant symptoms. 318 patients of the cohort had an index episode of mania and 424 patients had initial symptoms of depression. Demographic and clinical data were collected. All the patients were followed up for 24 months. Data on compliance with follow-up appointments and recurrence of symptoms after 6 months, 12 months, 18 months and 24 months were collected. Clinical characteristics were compared between the mania group and depression groups. 
Results: More bipolar patients had an index episode of depression [57.14% vs. 42.86%]. Compared with the depression group, the mania group had later age of diagnosis of bipolar disorder [(38.64±13.50) vs. (36.34±14.94), P=0.028], less education [(9.37±4.34) vs. (10.17±4.81), P=0.017] and greater latency between an initial episode of psychiatric symptoms and formal bipolar diagnosis [(10.80±10.76) vs. (8.85±9.90), P=0.012]. More patients in the mania group were male, without psychotic symptoms (all P<0.05). In comparison with the mania group, more patients in the depression group were female, with higher frequency of a reported precipitating event before index mood episode (all P<0.05). Compared with the depression group, the mania group had more recurrences of illness at the end of 12 months (Z=-2.156，P=0.031), 18 months (Z=-2.192，P=0.028) and 24 months (Z=-2.364,P=0.018). 
Conclusions: Our findings suggest more bipolar patients have an index episode marked by depressive symptoms. Bipolar patients with an index episode of mania have later age of diagnosis, less education and longer latency between a first episode of psychiatric symptoms and formal diagnosis of bipolar disorder. Patients with depressive symptoms of bipolar disorder at time of index hospitalization are more likely to have had some precipitating event, higher education level and lower recurrence rates