The Long-Term Consequences of Sibling Bullying

• In Event: 1-071 - Sibling Bullying: Precursors and Consequences

Integrative Statement

Theories on the development of psychopathology have mainly focussed on the trauma inflicted by parents on children either directly (e.g. abuse) or indirectly (e.g. domestic violence). The last decade has shown convincing evidence that peer bullying has similar adverse impact on mental health as parental abuse. Surprising is, however, that the consequences of bullying between siblings has been completely neglected in theories of the development of psychopathology as well as in empirical research.

We conducted a longitudinal study using data from >6900 participants of a UK community-based birth cohort (Avon Longitudinal Study of Parents and Children). Both peer bullying (in elementary and secondary school) and sibling bullying at 12 years were assessed. Mental health outcomes were measured with standard psychiatric interviews and antisocial behaviour using self-reports and crime record information at 18-20 years of age. All logistic regression analyses were controlled for social, disadvantage, maladaptive parenting, domestic violence experience, peer bullying and parental mental health.

The findings were as following: Firstly, children who were frequently bullied were approximately twice as likely to have depression (OR=2.16; 95% CI, 1.33–3.51), self-harm (OR=2.56; 95% CI, 1.63–4.02), and anxiety (OR=1.83; 95% CI, 1.19–2.81) compared to uninvolved children. The ORs were only slightly attenuated after adjustment for a range of confounding individual, family, and peer factors. The population-attributable fractions suggested that 13.0% (95% CI, 1.0%–24.7%) of depression and 19.3% (95% CI, 7.6%–29.6%) of self-harm could be explained by being the victim of sibling bullying if these were causal relationships. Secondly, involvement in sibling bullying was associated with psychotic disorder in a dose-response fashion, even after controlling for a range of confounders. Those involved several times a week were 2–3 times more likely to meet criteria for a psychotic disorder (victimization: OR=2.74; CI, 1.28–5.87; perpetration: OR=3.16; CI, 1.35–7.41. Categorical analysis indicated that particularly victims (OR=3.10; CI 1.48–6.50) and bully-victims (OR 2.66; CI 1.24–5.69) were at increased risk of psychotic disorder. Involvement in both sibling and peer bullying had a dose-effect relationship, with those victimized in both contexts having more than four times the odds for a psychotic disorder (OR=4.57; CI 1.73–12.07). Thirdly, frequent sibling bullying perpetration predicted antisocial behavior (OR=1.74; 95% CI, 1.38-2.20), while frequent sibling bullying victimization increased the odds of nicotine dependence (OR=2.87; 95% CI, 1.55-5.29), even after accounting for peer bullying and parent maltreatment. Finally, this study found that adolescents who were involved in bullying perpetration across multiple contexts (home and school) had the highest odds of reporting antisocial behavior (OR=3.05; 95% CI, 2.09-4.44), criminal involvement (OR=2.12; 95% CI, 1.23-3.66) and illicit drug use (OR=2.11; 95% CI, 1.44-3.08).

In conclusion, being victimised or being a victim who retaliates (bully/victim) is associated with adverse serious mental health outcomes including self-harm, depression, psychotic disorder and antisocial behaviour and crime. These findings indicate that developmental psychopathology theories need to include sibling bullying as a major risk factor and there is an urgent need to develop interventions to help victimised siblings and their families.

Authors

• Dieter Wolke, University of Warwick
  Presenting Author

• Slava Dantchev, University of Warwick
  Non-Presenting Author