2. Methods
2.1. Participants
This study was conducted at 6 university hospitals in South
Korea, from March 2, 2011 to August 30, 2012. A total of 164 patients
with MDD were voluntarily enrolled from the psychiatric
outpatient clinics. The Institutional Review Boards of Samsung
Medical Center and of each participating center approved the
study and it was officially registered (ClinicalTrials.gov identifier
NCT01309776). Participants provided written informed consent
prior to entry. The study was designed and performed as an investigator
initiated trial (IIT) and was entirely conducted under the
responsibility of the principal and co-investigators.