The aim of this cohort study is to observe the prevalence, incidence, relapse, and remission rates of online and/or smartphone game addiction among elementary and secondary school students in Korea. In addition the investigators are going to identify risk and protective factors, to determine whether online and/or smart phone game addiction is a primary or secondary problem, and to identify outcomes for individuals who become or stop being online and smart phone game addiction.

Participants:

Total 3,000 children will be enrolled the cohort and followed up for 4 years.

Procedures:

These students will be surveyed annually between 2015 and 2019. Surveys were conducted in classrooms by trained interviewer who had been trained by the research team assisted by the teachers.

Measurements

• usage and frequency of internet, internet game, and smartphone game etc.
• interpersional relationship; with family members, peer group, and teacher etc.
• personal characteristics; self esteem, social support, depression, anxiety, hyperactivity etc.
• Socio-demographic factors

Inclusion Criteria:

• 3rd, 4th, and 7th grade students of selected 15 elementary and secondary schools who provide consent both the students and their parents

Exclusion Criteria:

• does not provide consent

Tatal 3,000 elementaty and sencondary school students