1. Department of Psychiatry, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Workplace Mental Health Institute, Kangbuk Samsung Hospital, Seoul, Korea.
3. Department of Psychiatry, Chung-Ang University Medical Center, Chung-Ang University College of Medicine, Seoul, Korea.
4. School of Social Welfare, Soongsil University, Seoul, Korea.