Children who were bullied by siblings were significantly more likely to experience depression, anxiety and self-harm by early adulthood compared with children who were not bullied by their siblings, according to study findings in Pediatrics.
Lucy Bowes, PhD, of the University of Oxford, United Kingdom, and colleagues assessed the effects of sibling bullying using data for more than 6,000 families from the Avon Longitudinal Study of Parents and Children. Children of mothers who were recruited for the initial study were invited to nine assessment clinics, including in-person interviews and psychological and physical tests, from age 7 years onward. Children answered questions on sibling bullying at a mean age of 12 years. Depression, anxiety and self-harm were assessed at a mean age of 18 years.
Children who were bullied by siblings most commonly experienced nonphysical bullying, such as name calling (23.1%) or being made fun of (15.4%) several times a week.
Children who were bullied had higher levels of emotional and behavioral problems when aged 7 years and had higher rates of peer victimization.
Bullied children were more likely to be female and to have an older sibling, specifically an older brother. They were also more likely to live in families with three or more children.
Lower social class and higher levels of maternal depression during pregnancy were associated with more frequent sibling bullying. Sibling bullying occurred more often in families with higher levels of domestic violence and mistreatment of children.
More than half (n=1,810) of the 3,452 children who provided data for sibling bullying and psychiatric outcomes at 18 years said they had not experienced sibling bullying. Of these, 6.4% had clinically significant depression levels at age 18 years; 9.3% experienced anxiety; and 7.6% had self-harmed in the previous year. Approximately 12% of the 786 children who experienced sibling bullying reported depression at age 18 years; 16% reported anxiety; and 14.1% reported self-harm.
Children who experienced sibling bullying several times a week were more than two times as likely to experience depression (OR=2.16; 95% CI, 1.33-3.51) or self-harm (OR=2.56; 95% CI, 1.63-4.02) at age 18 years compared with those who were not bullied by siblings. Further, children who experienced frequent sibling bullying had a higher risk for anxiety at age 18 years (OR=1.83; 95% CI, 1.19-2.81).
Researchers found no association between gender and sibling bullying regarding depression, anxiety or self-harm outcomes.
“Although sibling bullying tends to occur more often in families characterized by high levels of conflict and violence, our findings suggest that sibling bullying is independently associated with the emergence of depression and self-harm once such family risk factors have been taken into account,” the researchers wrote.
They said their findings indicate a need for the development of interventions designed to specifically target sibling bullying.
Disclosure: The researchers report no relevant financial disclosures.