Fortunately, I had a wonderful childhood. My parents weren’t just my parents, but companions who knew when to give, push, and encourage. And I couldn’t have asked for better siblings: my three brothers protected me (without taking it too far), and my three sisters offered constant support and guidance.

I’m truly blessed to have had such an easy and enjoyable upbringing—considering not everybody is so lucky. Unlike myself, some kids grow up in physically, mentally, or emotionally abusive homes. You’re probably picturing a scared or sad child being mistreated by his parents—while this narrative is a reality for many, the truth is that parents aren’t the only offenders… siblings cause physical and emotional harm as well. And according to new research, the negative effects of sibling bullying are extensive. This study “Sibling bullying in middle childhood and psychotic disorder at 18 years: a prospective cohort study” says kids who are bullied by siblings are three times more likely to be diagnosed with a psychiatric disorder during adulthood.

This study, which was led by Dieter Wolke at the University of Warwick’s Department of Psychology, is the first of its kind, as no other study has explored the relationship between sibling bullying and the development of psychotic disorders. Wolke’s team made this discovery after analyzing questionnaire data from the Avon Longitudinal Study of Parents and Children. Approximately 3,600 individuals completed this questionnaire on sibling bullying at the age of 12 and then went on to take a standardized clinical examination, which assessed psychotic symptoms, at the age of 18.

Out of the 3,600 study participants, 664 were victims of sibling bullying, 486 were the bullies, and 771 were bully-victims, whereas they bullied their siblings and were also bullied by their siblings. Wolke’s team made a few significant discoveries: 55 of the children had developed a psychotic disorder by the age of 18; the more frequently a child was involved in sibling bullying—whether they were the bully, victim, or both—the more likely they were to develop a psychotic disorder; and most notably, those involved in sibling bullying (in any regard) a few times a week or month are two to three more times likely to develop a psychotic disorder.

“Bullying by siblings has been until recently widely ignored as a trauma that may lead to serious mental health problems such as a psychotic disorder,” Wolke explains. “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 disorders—as shown here for the first time.”

Wolke’s team concludes that parents as well as healthcare professionals need to be aware of the long-term harmful consequences of sibling bullying. Furthermore, they call for interventions be developed to reduce and possibly prevent bullying within families and in households. This study shows that the recommended awareness and intervention is vital to the wellbeing of today’s children and future adults.

University of Warwick (2018, February 12). Sibling Bullying Makes Psychiatric Disorders 3 Times More Likely. NeuroscienceNews. Retrieved February 12, 2018 from

Dantchev, S., Zammit, S., & Wolke, D. (2018, February 12). Sibling bullying in middle childhood and psychotic disorder at 18 years: a prospective cohort study. Psychological Medicine. Retrieved on February 13, 2018 from