Supplementary Material for: Network structure and clustering analysis relating to individual symptoms of problematic internet use in a community adolescent population

Introduction: Problematic internet use (PIU) is a psychopathology that includes multiple symptoms and psychological constructs. Because no studies have considered both network structures and clusters among individual symptoms in the context of PIU in a Korean adolescent population, this study aimed to investigate network structures and clustering in relation to PIU symptoms in adolescents. Methods: Overall, 73,238 adolescents were included. PIU severity was assessed using a self-rating scale comprising 20 items and 6 subscales, namely, the Internet Addiction Proneness Scale for Youth–Short Form; KS-scale. Network structures and clusters among symptoms were analyzed using a Gaussian graphical model and exploratory graph analysis, respectively. Centrality of strength, closeness, and betweenness scores were also calculated. Results: Our study identified four clusters: disturbance in adaptive functioning, virtual interpersonal relationships, withdrawal, and tolerance. The symptom of confidence served as a node bridging the cluster of virtual interpersonal relationships and other clusters of withdrawal and disturbances of adaptive function. The symptom of craving served as a bridge between the clusters of withdrawal and tolerance with high betweenness centrality. Conclusion: This study identified network structures and clustering among PIU symptoms in adolescents and revealed that positive experiences derived from online interpersonal relationships were an important mechanism underlying PIU. These are novel insights concerning the interconnection among multiple symptoms and related clustering for the mechanism of adolescent PIU in terms of KS scale PIU assessment.

引言：问题性网络使用（Problematic Internet Use）是一类涵盖多种症状与心理构念的精神病理现象，以下简称PIU。目前尚无研究针对韩国青少年群体的PIU情境，同时考察其个体症状间的网络结构与聚类特征。为此，本研究旨在探究青少年PIU症状的网络结构及其聚类关联。
方法：本研究共纳入73238名青少年。采用包含20个条目、6个维度的自评量表测评PIU严重程度，该量表即青少年网络成瘾倾向量表简版（Internet Addiction Proneness Scale for Youth–Short Form，简称KS-scale）。分别采用高斯图模型与探索性图分析，对症状间的网络结构与聚类情况进行分析，并计算了强度、接近性与中介性三类中心性得分。
结果：本研究共识别出四类症状聚类：适应功能障碍、虚拟人际关系、戒断反应与耐受性。其中，自信心症状作为节点，起到了连接虚拟人际关系聚类与戒断反应、适应功能障碍两类聚类的桥梁作用；渴求症状则作为中介节点，连接了戒断反应与耐受性聚类，且具有较高的中介性中心性。
结论：本研究明确了青少年PIU症状间的网络结构与聚类特征，并揭示出源自线上人际关系的正向体验是PIU的重要潜在机制。针对基于KS量表开展的青少年PIU评估，本研究在多症状间的关联及其相关聚类机制方面取得了创新性见解。