Dose-Response Relationship of Loneliness and Internet Addiction With Depression Among College Students: A Multicenter Survey

Background: Depression in young people especially among college students is a growing concern. Both loneliness and Internet addiction are found to be linked to depression. Aims: This study explored the dose-response relationship of loneliness and Internet addiction with depression, and examined how the severity of loneliness and Internet addiction influence the susceptibility to depression. Methods: A cross-sectional study was conducted between September and December 2023 in China. Depression was evaluated using the 9-item Patient Health Questionnaire (PHQ-9). Loneliness and Internet addiction were assessed using the 20-item University of California, Los Angeles Loneliness Scale (UCLA-20) and Young’s 20-item Internet Addiction Test (IAT-20), respectively. Univariate and multivariate analyses were performed to explore the correlates of depression. Restricted cubic spline (RCS) analysis was employed to examine the potential dose-response relationships between the continuous exposure variables (loneliness and Internet addiction) and depression. Results: Among 6,514 college students included in the study, the prevalence of depression was 18.2% (95% confidence intervals, CI [17.3%, 19.1%]). After adjusting for confounders, a positive linear relationship was observed between loneliness and the risk of depression; while a J-shaped nonlinear relationship was found with an inflection point of 41 between Internet addiction and the risk of depression. Poor health and economic status also increased the risk of depression for college students with Internet addiction. Conclusions: Loneliness and Internet addiction both predicted the high risk of depression among college students. Mental health screening and interventions should be tailored to address loneliness and Internet addiction in this population to prevent the onset of depression among at-risk individuals.