There is only one Korean study so far on antidepressant adherence, which is the most important factor on the success of depression drug therapy, though depression is a major disease with a significant burden on patients.The objectives of this study is to seek for more effective treatment of depression in Korea by identifying factors

affecting adherence and to help clinical practice guideline development by providing cost effectiveness analysis among different treatment paths.

Since the antidepressants have various spectrums of efficacy and side effects profiles and there is no study showing an absolute superiority among them, there exists a difficulty selecting a first line therapy. One of the major long term goal of the Clinical Research Center for Depression (CRCD) is to develop a Korean clinical practice guideline on depression and this study on cost effectiveness analysis on treatment paths will be helpful for the guideline development.

In this study, extensive literature reviews and outcomes research using the Health Insurance Review Agency (HIRA) claims database from January 1, 2006 to December 31, 2008 (3 years) on patients characteristics, antidepressants prescribing patterns, medication adherence patterns and related factors were performed and a cost effectiveness analysis model was developed based on these results.