WARWICK, England — Maybe there’s more harm to a supposedly healthy sibling rivalry after all. Children who experience bullying by their siblings are up to three times as likely to develop psychotic disorders, such as schizophrenia or bipolar disorder, in early adulthood, a recent study finds.

Researchers from Warwick University say their study showed that bullied children aren’t the only ones at risk. They found all parties involved in childhood bullying — whether perpetrator or victim —were more likely to suffer from the mental health conditions the more they bullied or were bullied.

“Bullying by siblings has been until recently widely ignored as a trauma that may lead to serious mental health problems such as psychotic disorder,” says senior author Dieter Wolke, a professor in the university’s psychology department, in a media release. “Children spend substantial time with their siblings in the confinement of their family home and if bullied and excluded, this can lead to social defeat and self-blame and serious mental health disorder – as shown here for the first time.”

In what the authors are calling the first study ever to examine the association of sibling bullying and psychotic disorders, the research team examined questionnaires from about 3,600 12-year-old children who participated in large scale study about sibling bullying. Participants also filled out standardized clinical exams when they were 18 to determine if they showed symptoms of any psychotic disorder.

In all, 664 participants reported they were victims of sibling bullying, while 486 were bullies to their brothers or sisters at age 12. Fifty-five of the participants reporting developing a psychotic disorder diagnosis by 18 years of age.

Ultimately, the researchers calculated that children who were victims of sibling bullying were most at risk of developing the disorder. The study showed that the more frequently a person was bullied by their brother or sister, the greater the odds rose — with those battling attacks several times a week or month being two to three times more likely to having a psychotic condition.

Children being victimized at school and at home were especially at risk, with researchers calculating they’re four times more likely to suffer from a disorder.

“Although we controlled for many pre-existing mental health and social factors, it cannot be excluded that the social relationship problems may be early signs of developing serious mental health problems rather than their cause,” says first author Slava Dantchev.

The authors believe parents should be better educated in the psychological effects of bullying between siblings. Awareness can lead to prevention and allow the children to develop healthier behavior as they mature.

The full study was published Feb. 12, 2018 in the journal Psychological Medicine.

About Ben Renner

Writer, editor, curator, and social media manager based in Denver, Colorado. View my writing at

Our Editorial Process

StudyFinds publishes digestible, agenda-free, transparent research summaries that are intended to inform the reader as well as stir civil, educated debate. We do not agree nor disagree with any of the studies we post, rather, we encourage our readers to debate the veracity of the findings themselves. All articles published on StudyFinds are vetted by our editors prior to publication and include links back to the source or corresponding journal article, if possible.

Our Editorial Team

Steve Fink


Chris Melore


Sophia Naughton

Associate Editor