Network structure and behavioral mediation of depressive symptoms in left-behind children: differentiating single- and double-parent absence in a multicenter cross-sectional study

Parental absence in China, predominantly driven by labor migration, has created a substantial population of left-behind children, who face increased vulnerability to mental health disorders, particularly depression. However, the specific characteristics and interrelationships of depressive symptoms in this vulnerable population remain poorly elucidated, limiting the development of targeted interventions. This study recruited 3,458 adolescents (aged 12–17) from seven representative counties across China. Network analysis was employed to examine depressive symptom structures, and mediation analyses with bootstrap resampling were conducted to assess the indirect effects of lifestyle and dietary factors. E-value analyses were used to evaluate robustness to unmeasured confounding. Depressive symptoms were significantly elevated only in double-parent left-behind children, not in single-parent left-behind children. Symptom networks differed markedly: sadness, fatigue, and fearfulness were central in single-parent left-behind children, whereas loneliness and depressed mood dominated in double-parent left-behind children. Mediation analyses revealed substantial mediation by lifestyle and dietary factors in both subgroups. Screen time and low-intake dietary patterns were shared mediators across both subgroups. Reduced parental companionship mediated depression in single-parent left-behind children subgroup, whereas reduced outdoor activity mediated depression in double-parent left-behind children subgroup. E-value analyses indicated moderate robustness for total indirect effects. This study reconceptualizes left-behind status from a uniform risk factor to a differentiated construct, revealing that distinct patterns of parental absence are associated with unique depressive symptom profiles through diverging behavioral pathways. Interventions should shift from addressing psychological crises in isolation toward comprehensive psychosomatic promotion strategies—strengthening parental engagement for single-parent left-behind children, promoting outdoor activities alongside managing screen time and diet for double-parent left-behind children.