Background: Exploring networks of mental and behavioral problems in children and adolescents may identify differences between one-child and multi-child families. This study compared the network structures of mental and behavioral problems in children and adolescents in one-child families versus multi-child families based on a nationwide survey.

Methods: Propensity score matching (PSM) was used to match children and adolescents from one-child families with those from multi-child families. Mental and behavioral problems were assessed using the Achenbach's Child Behavior Checklist (CBCL) with eight syndromal subscales. In the network analysis, strength centrality index was used to estimate central symptoms, and case-dropping bootstrap method was used to assess network stability.

Results: The study included 39,648 children and adolescents (19,824 from one-child families and 19,824 from multi-child families). Children and adolescents from multi-child families exhibited different network structure and higher global strength compared to those from one-child families. In one-child families, the most central symptoms were “Social problems”, “Anxious/depressed” and “Withdrawn/depressed”, while in multi-child families, the most central symptoms were “Social problems”, “Rule-breaking behavior” and “Anxious/depressed”.

Conclusion: Differences in mental and behavioral problems among children and adolescents between one-child and multi-child families were found. To address these problems, interventions targeting “Social problems” and “Anxious/depressed” symptoms should be developed for children and adolescents in both one-child and multi-child families, while other interventions targeting “Withdrawn/depressed” and “Rule-breaking behavior” symptoms could be useful for those in one-child and multi-child families, respectively.