Precursors of Sibling Bullying in Middle Childhood: Evidence from a UK-Based Longitudinal Cohort Study

Background: There is increasing evidence that sibling bullying is associated with various social, emotional, and mental health difficulties. It is, however, unclear which factors predict sibling bullying in middle childhood and whether child-level individual differences make some children more susceptible to sibling bullying involvement. Objective: To investigate the precursors of sibling bullying in middle childhood in a UK based population sample. Participants and Setting: Existing data from the prospective Millennium Cohort Study (N=16,987) was used. Primary caregivers reported on precursors (child age 7 years or earlier) whilst children self-reported on sibling bullying (child age 11 years). Analysis: A series of multinomial logistic regression models were fitted. First, testing for crude associations between sibling bullying and the precursors individually. Culminating in a final model with the significant predictors from all of the previous models. Results: Structural family-level characteristics (e.g. birth order, ethnicity, and number of siblings) were found to be the strongest predictors of sibling bullying involvement followed by child-level individual differences (e.g. emotional dysregulation and sex). Parenting and parental characteristics (e.g. primary caregiver self-esteem and harsh parenting) predicted sibling bullying, but to a lesser extent. Conclusions: These findings suggest that structural family characteristics and child-level individual differences are the most important risk factors for sibling bullying. If causality can be established in future research, they highlight the need for interventions to be two-pronged: aimed at parents, focusing on how to distribute their time and resources appropriately to all children, and the children themselves, targeting specific sibling bullying behaviors.