Although the comorbidity of post-traumatic stress symptoms (PTSS) and depressive symptoms is well-documented across various traumatic events, the comorbidity network among school bullying victims remains understudied, particularly concerning potential gender differences. The overlapping symptoms hypothesis posits that shared symptoms between PTSS and depressive symptoms drive their comorbidity, which has been rarely tested using network analysis. Therefore, this study aimed to examine the comorbidity network characteristics of PTSS and depressive symptoms among adolescent victims of school bullying, focusing on how these symptoms manifest differently across gender groups through the application of network analysis method. A total of 724 adolescents who were victims of school bullying participated in the survey, and this study was conducted using the Chinese version of the Delaware Bullying Victimization Scale, the PTSD Checklist for DSM-5, and the Chinese version of the Center for Epidemiologic Studies Depression Scale for Children.

The results showed that in the overall sample of this study, the nodes with higher expected influence (EI) in the network were grief, flashback, sadness, no positive emotion, detachment, and concentration problems. The primary bridge symptoms connecting the PTSS and depressive symptom networks were no positive emotion, detachment, concentration problems, cannot concentrate, feeling fearful, and negative beliefs. However, attentional problems were the overlapping symptoms shared by PTSS and depressive symptoms.

Furthermore, the results revealed that there were no significant differences in the structure or overall strength of the PTSS-depressive symptoms networks between male and female adolescents. However, there were similarities and differences in the central symptoms and bridge symptoms of the comorbidity networks. Notably, overlapping symptoms of PTSS and depressive symptoms, specifically attention problems and negative emotions, were identified only in the male group, with these symptoms demonstrating stronger bridge centrality.

Specifically, among boys, the symptoms of grief, sadness, flashback, detachment, and irritability and anger exhibited stronger EI. The main bridge symptoms in the comorbidity network of PTSS and depressive symptoms among boys were concentration problems, cannot concentrate detachment, no positive emotion, sadness, and people dislike me. Therefore, attention problems and negative emotions were overlapping symptoms of PTSS and depressive symptoms in boys who have experienced school bullying. In the PTSS-depressive symptoms comorbidity network among bullying victimized girls, flashback, grief, no positive emotion, concentration problems, and feeling tired were identified as central symptoms. The main bridge symptoms in the girls’ PTSS and depressive symptoms network were no positive emotion, feeling fearful, detachment, hard to do something and sleep problems. It could be seen that grief and flashback were central symptoms common to both genders, while detachment and no positive emotion served as shared bridge symptoms.

Theoretically, these findings provide gender-specific support for the overlapping symptoms hypothesis. While the boys' comorbidity network was driven by both overlapping (e.g., attention problems, negative emotions) and non-overlapping bridge symptoms (e.g., people dislike me), the girls’ network was driven exclusively by non-overlapping symptoms (e.g., feeling fearful, hard to do something). Practically, this study offers a prioritized intervention framework for bullying-victimized adolescents. First, targeting shared bridge symptoms (e.g., detachment, no positive emotion) can disrupt cross-diagnostic connectors, yielding broad effectiveness across both genders. Second, treatments should be tailored to gender-specific dynamics—prioritizing overlapping symptoms in boys and distinct non-overlapping symptoms in girls. Taken together, these findings highlight the value of integrating transdiagnostic and gender-specific strategies in treating PTSS and depressive symptoms.