1. Department of Psychiatry, Korea University College of Medicine, Korea University Ansan Hospital, Ansan, Korea.
2. Division of Health and Nutrition Survey, Centers for Disease Control and Prevention, Cheongju, Korea.
3. Department of Psychiatry, Daegu Catholic University Medical Center, Daegu, Korea.
4. Department of Psychiatry, Korea University College of Medicine, Korea University Guro Hospital, Seoul, Korea.
5. Department of Psychiatry, Sungkyunkwan University School of Medicine, Seoul, Korea.