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Time to relapse and remission of bipolar disorder: findings from a 1-year prospective study in Thailand

Authors Leelahanaj T, Kongsakon R, Choovanicvong S, Tangwongchai S, Paholpak S, Kongsuk T, Srisurapanont M 

Received 6 May 2013

Accepted for publication 5 June 2013

Published 22 August 2013 Volume 2013:9 Pages 1249—1256


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Thawatchai Leelahanaj,1 Ronnachai Kongsakon,2 Somrak Choovanichvong,3 Sookjaroen Tangwongchai,4 Suchat Paholpak,5 Thoranin Kongsuk,6 Manit Srisurapanont7

For the Thai Bipolar Registry Study Group

1Department of Psychiatry and Neurology, Phramongkutklao Hospital, Bangkok, Thailand; 2Department of Psychiatry, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Srithanya Hospital, Nonthaburi, Thailand; 4Department of Psychiatry, Chulalongkorn University, Bangkok, Thailand; 5Department of Psychiatry, Khon Kaen University, Khon Kaen, Thailand; 6Prasrimahabhodi Psychiatric Hospital, Ubon Ratchathani, Thailand; 7Department of Psychiatry, Chiang Mai University, Chiang Mai, Thailand

Background and methods: This study aimed to determine time to relapse and remission of mood episodes in Thai patients with bipolar disorder (BD). The Thai Bipolar Disorder Registry was a multicenter, prospective, naturalistic, observational study conducted in Thailand. Participants were adult inpatients or outpatients with Diagnostic and Statistical Manual of Mental Disorders bipolar disorder. The diagnosis of bipolar disorder, current psychiatric comorbidity, mood relapse, and mood remission were determined by using the Mini International Neuropsychiatric Interview. Relapse and remission were assessed every 2 months.
Results: Of 424 BD participants, 404 (95.3%) were BD I, and 258 (60.8%) were female. At entry, 260 (61.3%) had recovered, and 49 (11.6%) were recovering. During 1-year follow-up (381.7 person-years), 92 participants (21.7%) had 119 relapses or 0.31 (95% confidence interval 0.25–0.35) episodes per person-year. Among 119 relapses, 58 (48.7%), 39 (32.7%), and 21 (17.6%) of them were depressive, hypomanic, and manic episodes, respectively. Using the Kaplan–Meier method, we found that 25% of the participants relapsed in 361 days. Of the 400 participants who reached remission, 113 (28.2%) had mood relapses. Of 173 mood events accountable for remission analysis, the median time to remission was 67.5 days (72.5 days for depressive episodes versus 58.0 days for manic episodes, log rank P = 0.014).
Conclusions: The 1-year relapse rate in Thai patients with BD was 21.7% or 0.31 episodes per person-year. About one-fifth of recovered patients had mood relapses within 371 days. On average, a mood episode would remit in 67.5 days.

Keywords: bipolar disorder, course, outcome, relapse, remission, Thai

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