1. Department of Psychiatry, School of Medicine, Jeju National University, Jeju, Korea.
2. Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA.
3. Department of Disability and Human Development, University of Illinois, Chicago, IL, USA.
4. Department of Psychiatry, Yonsei University, Seoul, Korea.
5. Child Study Center, Yale University School of Medicine, New Haven, CT, USA.
6. Department of Psychiatry, Chonbuk National University Medical School, Jeonju, Korea.
7. Research Institute of Clinical Medicine of Chonbuk National University, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Korea.
8. Jeonbuk Internet Addiction Center, Jeonju, Korea.
9. Jeonju Dong Middle School, Jeonju, Korea.