Study protocol of the internet user Cohort for Unbiased Recognition of gaming disorder in Early adolescence (iCURE), Korea, 2015–2019

INTRODUCTION: In 2013, the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) proposed nine internet gaming disorder (IGD) diagnostic criteria as a condition warranting further empirical and clinical research. The aim of this study is to clarify the natural and clinical courses of IGD proposed DSM-5 in adolescents and to evaluate its risk and protective factors. METHODS AND ANALYSIS: The Internet user Cohort for Unbiased Recognition of gaming disorder in Early Adolescence (iCURE) study is an ongoing multidisciplinary, prospective, longitudinal cohort study conducted in 21 schools in Korea. Participant recruitment commenced in March 2015 with the goal of registering 3000 adolescents. The baseline assessment included surveys on emotional, social and environmental characteristics. A parent or guardian completed questionnaires and a structured psychiatric comorbidity diagnostic interview regarding their children. Adolescents with the Internet Game Use-Elicited Symptom Screen total scores of 6 or higher were asked to participate in the clinical diagnostic interview. Two subcohorts of adolescents were constructed: a representative subcohort and a clinical evaluation subcohort. The representative subcohort comprises a randomly selected 10% of the iCURE to investigate the clinical course of IGD based on clinical diagnosis and to estimate the false negative rate. The clinical evaluation subcohort comprised participants meeting three or more of the nine IGD criteria, determined by clinical diagnostic interview, to show the clinical course of IGD. Follow-up data will be collected annually for the 3 years following the baseline assessments. The primary endpoint is 2-year incidence, remission and recurrence rates of IGD. Cross-sectional and longitudinal associations between exposures and outcomes as well as mediation factors will be evaluated. ETHICS AND DISSEMINATION: This study is approved by the Institutional Review Board of the Catholic University of Korea. Results will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (identifier: NCT02415322).