*The following is excerpted from an online article posted on PsychCentral.
A new study from U.K. researchers suggests those who were bullied by siblings in childhood are up to three times more likely to develop psychotic disorders in young adulthood.
Moreover, if a child is bullied at home by a sibling and then again at school, they were four times more likely to develop a psychotic disorder.
Psychotic disorders can include schizophrenia and bipolar disorder and can cause abnormal thoughts and perceptions, often involving hallucinations or delusions. Sufferers often experience severe distress and changes in behavior and mood and have an elevated risk of suicide and health problems.
The study, found in the journal Psychological Medicine, is the first to review the relationship between sibling bullying and the development of psychotic disorders.
University of Warwick investigators followed almost 3,600 students participating in the Avon Study of Parents and Children, a longitudinal study of parents and children.
The study format had both parents and children completing a detailed questionnaire on sibling bullying at twelve years of age, and then subsequently filling out a standardized clinical examination assessing psychotic symptoms when the child was eighteen years old.
Professor Dieter Wolke and colleagues discovered that among adolescents, 664 were victims of sibling bullying, 486 children were pure bullies to their siblings, and 771 children were bully-victims (victimized by siblings and bullied their siblings), at age twelve.
Wolke’s team discovered 55 of the total 3600 children in the study had developed a psychotic disorder by the age of eighteen.
The researchers found that the more frequently children are involved in sibling bullying — either as bully, victim, or both — the more likely they are to develop a psychotic disorder.
Those involved in sibling bulling (as bully or victim) several times a week or month are two to three times more likely to develop a psychotic disorder than other kids.
The children most at risk are victims of sibling bullying, and those who both become victims and bully their siblings (bully-victims).
Children who are victimized both at home and by school peers are even worse off; the study found them four times more likely to develop psychotic disorders than those not involved in bullying at all.
The researchers concluded that parents and health professionals should be made aware of the long-term mental health consequences that sibling bullying may have.
This knowledge will hopefully allow the development of interventions that reduce and even prevent this form of aggression within families.