1. Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
2. Department of Psychiatry, Jeonbuk Provincial Maeumsarang Hospital, Wanju, Republic of Korea.
3. Center for Clinical Research, Samsung Biomedical Research Institute, Seoul, Republic of Korea.
4. Biostatistics Unit, Samsung Biomedical Research Institute, Seoul, Republic of Korea.