Association between loneliness trajectories and chronic diseases as well as chronic comorbidities among middle - aged and elderly chinese: based on the group - based trajectory modeling method.

Bullying in school is typically defined as systematic, intentionally harmful behavior characterized by a power imbalance between bullies and victims (Volk et al., ). It is a pervasive problem associated with substantial short- and long-term maladjustment for both victims and perpetrators, including internalizing problems, academic difficulties, and later externalizing and psychiatric problems (Cunningham et al., ; Schoeler et al., ; Ye et al., ). Bullying does not occur in isolation, however; it unfolds within a broader peer ecology in which bystanders play a central role in maintaining or challenging harmful social dynamics (Salmivalli et al., ). In this respect, defending victimized peers is often seen as a promising strategy to reduce bullying and improve victims’ adjustment, yet defending may also expose defenders themselves to social risks. However, evidence on when defending is protective versus risky for defenders remains limited and mixed, particularly in primary school and with respect to the joint roles of individual status and classroom norms. This study addresses this gap by examining concurrent and longitudinal associations between defending and victimization in primary school classrooms, and by testing how these associations depend on children’s position in the peer group and the normative climate of their classroom. Defending is usually defined as comforting or supporting behaviors toward victims during or after bullying episodes, in which contemporary research distinguishes between at least two broad forms of defending: victim-oriented and bully-oriented defending (Meter & Card, ; Malamut et al., ). Victim-oriented defending includes behaviors such as comforting the victim, offering emotional support, or involving adults on the victim’s behalf, whereas bully-oriented defending involves directly confronting or challenging the perpetrator (Gini et al., ). These forms are likely to carry different social dynamics and risks. Publicly confronting a bully may involve more salient challenges to status and a higher risk of retaliation than quietly supporting a victim, even though both forms can signal opposition to bullying. Importantly, a consistent finding is that defending, independently of which form, benefits victims. Compared with undefended victims, those who have at least one defender report higher self-esteem, stronger feelings of belonging, and higher peer acceptance with less rejection (Laninga-Wijnen et al., ; Saarento et al., ; Sainio et al., ). Moreover, by encouraging prosocial behaviors, defending may also help create healthier social hierarchies in which respect and inclusion are prioritized over coercion and dominance, fostering a more positive and collaborative peer environment (Sainio et al., ). In contrast, when peers witness bullying but do not intervene, victims may experience heightened distress, anxiety, and depressive symptoms (Ye et al., ), and inaction may reinforce a passive peer environment that normalizes bullying (Pozzoli & Gini, ). For these reasons, many school-based interventions encourage defending behavior as a central strategy to address bullying (Salmivalli et al., ).