Research report The effects of continuous antidepressant treatment during the first 6 months on relapse or recurrence of depression ☆ Kyoung-Hoon Kim a , Seung-Mi Lee a , Jong-Woo Paik b , Nam-Soon Kim c, ⁎ a Review & Assessment Policy Institute, Health Insurance Review and Assessment Service, Seoul, Republic of Korea b Department of Psychiatry, College of Medicine, Kyung Hee University, Seoul, Republic of Korea c Health Policy Research Division, Korea Institute for Health and Social Affairs, Republic of Korea article info abstract Article history: Received 28 March 2010 Received in revised form 14 February 2011 Accepted 14 February 2011 Available online 12 March 2011 Background: To examine whether continuous antidepressant treatment during the first 6 month reduces the risk of relapse/recurrence of depression in South Korea. Methods: We used National Health Insurance Data covering the period from 2001 through 2004. The study population consisted of 117,087 adult patients who received antidepressants after being diagnosed with depression. The continuous antidepressant was defined as evidence of antidepressant prescriptions for 75% of the first 6 months of treatment. Relapse or recurrence during the next 18-month period was defined by evidence of a new episode requiring antidepressant treatment, psychiatric hospitalization, electroconvulsive therapy, emergency department visit or attempted suicide. We compared the relapse/recurrence rate during the 18-month follow-up period in patients receiving continuous treatment and those who discontinued early using a Cox's proportional hazard model. Results: Patients receiving continuous antidepressant treatment experienced a lower risk of relapse/recurrence (Hazard ratio: 0.42, 95% CI: 0.40–0.44). Three or more follow-up visits in the first 3 months also reduced the risk of relapse/recurrence. Factors associated with a significant increase of relapse/recurrence were comorbid medical illness, anxiety disorder, and alcohol abuse. The small benefit of SSRIs was appeared only in the early discontinued treatment subgroup, not in the continuous treatment subgroup. Limitations: We were not able to consider the antidepressant utilization pattern. Conclusions: Continuous antidepressant treatment and frequent follow-up visits during the acute phase were associated with a significant reduction in the likelihood of relapse or recurrence of depression. Our results provide important evidence on the effectiveness of antidepressant treatment in South Korea. © 2011 Elsevier B.V. All rights reserved. Keywords: Depression Antidepressant treatment Relapse Recurrence 1. Introduction Depression is a mental disease accompanied by symptoms in mood, cognition and motor functions, causing problems in one's work and social life, and affecting patients' general quality of life. Suicide risk appears to be in the range of 15% (Guze and Robins, 1970). According to the WHO, lifetime prevalence of major depression is around 10%, and around 350 million people are suffering from depression. The WHO predicted that depression will become the disease with the 2nd highest burden by 2020 (WHO, 2001). In Korea, the lifetime prevalence of depression was 5.6% in 2006, which was 1.6% higher than in 2001 (Ministry of Health and Welfare, 2007). Furthermore, the suicide rate in South Korea is quite high at Journal of Affective Disorders 132 (2011) 121–129 ☆ This study was performed as a research project of the Health Insurance Review & Assessment Service and funded from the HIRA budget. ⁎ Corresponding author at: Korea Institute for Health and Social Affairs, Jinhungro 707 Bulgwang-dong, Eunpyeong-gu, Seoul 122-705, Republic of Korea. Tel.: +82 2 380 8164; fax: +82 2 353 0344. E-mail addresses: artemine@kihasa.re.kr, artemine@hanmail.net (N.-S. Kim). 0165-0327/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jad.2011.02.016 Contents lists available at ScienceDirect Journal of Affective Disorders journal homepage: www.elsevier.com/locate/jad