Abstract: Objective To explore the independent and combined mediating effects of sleep quality and food addiction on the relationship between family environment and adolescent depression, providing evidence for the development of intervention strategies for adolescent depression. Methods From September to December 2022, a stratified random cluster sampling method was used to select adolescents from grades 4 to 12 in Yixing, Jiangsu Province. An online self-administered monitoring system was employed to survey adolescents using the Depression-anxiety-stress Scale (short version), Family Environment Scale, Insomnia Severity Index, and Yale Food Addiction Scale. Mediation models were constructed to analyze the mediating roles of insomnia and food addiction between family intimacy and depression. Results Among 4 180 students, 2 141 (51.2%) were male and 2 039 (48.8%) were female. The distribution across educational levels was 1 154 (27.6%) primary school students, 1 644 (39.3%) middle school students, and 1 382 (33.1%) high school students. The prevalence of depression was 16.6%. Students with low, moderate, and high family intimacy accounted for 414 (9.9%), 1 398 (33.44%), and 2 368 (56.65%), respectively. The prevalence of insomnia was 13.8%, and the prevalence of food addiction was 7.7%. Mediation model results showed that insomnia (mediating effect: -0.747, 95% CI: -0.841 - -0.659, accounting for 39.1% of the total effect) and food addiction (mediating effect: -0.098, 95% CI: -0.139 - -0.070, accounting for 5.1% of the total effect) had independent mediating effects. Additionally, insomnia and food addiction had a chain-mediated effect (mediating effect: -0.064, 95% CI: -0.091 to -0.043, accounting for 3.3% of the total effect). Conclusion Family intimacy directly affects adolescent depression and indirectly influences its development through the mediation of insomnia and food addiction.

Key words: Adolescent, Depression, Insomnia, Food addiction, Family intimacy, Mediating effect