ABSTRACT
In China, the Three-Child Policy has increased the proportion of adolescents with more siblings, offering a context to test resource dilution theory where parental resources per child decline as sibling number grows, potentially affecting mental health. Existing studies link larger sibling counts to higher adolescent depressive symptoms, but rely on scale total scores, ignoring that symptoms vary in impact. This approach masks specific symptom dimensions, hindering identification of high-risk domains. To address this, we compared depressive symptom networks in 1179 Chinese adolescents (no siblings vs. ≥ 1 sibling) using the 20-item Center for Epidemiological Studies Depression Scale through network analysis. Core findings showed unhappiness and sadness were central symptoms in both groups, but key differences emerged: adolescents with no siblings emphasised hopelessness and feeling disliked, while those with siblings prioritised depressed mood and perceived life failure. Despite similar network structures, sibship size influenced symptomatic profiles, suggesting interventions for clinical depression in Chinese adolescents may need tailoring based on the number of siblings to target unique high-risk symptoms.