Sibling bullying: humiliated and scorned by a family member . . . this is not just ‘sibling rivalry’

Sibling maltreatment is the most common form of domestic abuse in Western society

There is an urgent need to challenge the perception that it is acceptable for someone to harm you in any way if they are your sibling

Last year, I interviewed six victims of sibling bullying – all women. Most had experienced bullying or intense dislike from their earliest memories. For some, there was an identifiable starting point, such as parental separation.

The six women were bullied by a sibling immediately before or after them. Bullying involved relentless name-calling and put-downs, physical violence or threats (by brothers), taking or breaking property and a pervasive psychological intrusion. They spoke of feeling powerless, humiliated, of how stressful it was to live in that environment – and that their childhood and adolescence were unhappy as a result.

All the victims now have little or no contact with the sibling bully.

Bronagh (20) suffers from anxiety and eating disorders. She counts "15 years of being beaten down" by her sister as a major contributor, if not the cause. She startles easily, and distrusts others.


Danni (32) was relentlessly bullied by her only sibling all her life, ripped to shreds verbally, physically attacked, monitored and controlled, her pet tortured, and personal possessions damaged. She suffered serious mental health issues by mid-teens which her sibling then used to discredit her accounts. About her stay in a psychiatric ward in her teens, she says: “It was great, I didn’t have to worry.”

One in three

Prof Mark Kiselica, of Cabrini University, Pennsylvania, describes sibling maltreatment as the most common form of domestic abuse in Western society, more common than domestic partner abuse or child abuse. Studies consistently find between one-third and one-half of children (under 18) are involved in sibling bullying. The small online survey conducted at UCD found that 31 per cent of participants considered they had been bullied by a sibling.

Sibling bullying is significantly more prevalent (as much as three times) than school bullying.

Yet, as Kiselica says, it “remains a forgotten abuse”.

Who are the bullies?

Sibling bullying is different to the usual family rows and bickering. Bullying, in any context, is a repeated, intentional, targeted aggression towards someone who finds it hard to defend themselves, where there is a real, or perceived, difference in power. It can be psychological, verbal, physical, cyber, involve property or exclusion.

Victims can be eldest, middle or youngest children, be bullied by brothers or sisters, older and younger. There is some evidence that boys are more likely to bully a younger sibling, while girls are more likely to bully an older sibling. Bullying tends to increase with family size, but severe bullying occurs also in families of two children. Bullying is more likely between siblings close in age, and even more likely to be between consecutive siblings. Results from the online survey found 37 per cent of bully-victim dyads were one to two years apart while 29 per cent were 2-4 years apart.

Bullies are not always easily identifiable. They can be nice in other contexts. Studies have found they are as popular, with as many friends, as non-bullies. Even though there is a strong correlation with school bullying (both as bully and victim) some are “niche” bullies – only in the home, harder to detect. What bullies commonly share are low levels of empathy and a highly developed theory of mind (the ability to understand the state of another person’s mind and emotions). Bullies are skilled at manipulating the fears and insecurities of their victim and calculating who should or should not witness.

Prof Dan Olweus, the Swedish pioneer of bullying research says that bullies generally (if not always) realise that their behaviour causes distress and pain. Victims spoke of their sibling's tangible pleasure inflicting pain. But then, intimate displays of power often do arouse pleasure.

Rachel (25) equates it to domestic abuse, “towering over me, not allowing me to leave rooms, blocking my personal space, following me, insulting and humiliating me”.


Prof Dieter Wolke from the University of Warwick – in England's West Midlands – is a leading researcher of sibling bullying, and cites parental behaviour and dysfunctional family structures as more influential than any demographic or socioeconomic factor. Marital difficulties and harsh or uninvolved parenting are all factors. Wolke cites parental differential treatment and real or perceived favouritism as potentially the most influential factor.

Bullying in any context is motivated by inequalities and a desire to improve one’s status. Children from very young are capable of perceiving differential treatment and may respond by attempting to raise their own status, by dominating and essentially demoting their rival sibling. One victim said about her sister: “She wanted me gone, or at least denied a valid role in the family.”

Bullying is most prevalent within middle-class well-educated families, fuelled perhaps by a culture of competitiveness and achievement. Tracy (56) says that “people think in a white, middle class family this couldn’t happen. Nobody believes you”.

Mental health

There is a well-established association between being bullied and mental health difficulties. A UK study in 2014 (with over 6,000 children) in which Wolke collaborated found that being bullied by a sibling at age 12 doubled the odds of depression, anxiety and self-harm by age 18.

What is less documented are the long-term effects, including residual mental distress and psychological problems. Family relationships can be fractured – particularly when parents (and others) continue to view the problem as a relational issue between two people, even blaming the victim for alienating themselves.


Sibling bullying is misconstrued as “sibling rivalry” – a term first coined by child psychiatrist Levy in the 1940s to describe an older sibling’s jealousy of a new baby, carrying connotations of natural, instinctive behaviour.

For those on the receiving end it is much, much more.

Normalisation of this abuse is arguably its greatest fuel and inevitably results in a lack of social support for victims. An American study published in 2016 in the Journal of Family Violence found that responses most frequently encountered when victims reported sibling violence to a parent or adult were; that it is 1) normal, 2) not serious, 3) the victim's fault, 4) a private matter or 5) taboo.

As Bronagh put it, nobody wants to hear about “weird family stuff”.

Parents appear to be reluctant to identify the behaviour as abusive, even blaming the victim for provoking the bully. They commonly tell victims on reaching 18, that the problem is now out of their hands.

Most parents simply do not know what to do.

There is an urgent need to challenge the perception that it is acceptable for someone to harm you in any way if they are your sibling. If most sibling bullying only ends when the victim or sibling leaves the home then resolution is not occurring.

Victims are left isolated, often alienated from family-life.

The negative effects on mental health are long-term.

In the words of one victim “buying a TV for my room wasn’t the answer. You have to stop it”.

Emma O'Friel conducted her thesis on sibling bullying for a Master's in Psychology at UCD.

Sibling bullying series

- Humiliated and scorned by a family member . . . this is not just 'sibling rivalry'
- 'I hate him but I'll still answer the phone to him . . . '
- 'It continued until at age 30 . . . I walked away'
- 10 readers on sibling bullying: 'My brother hated me from my birth – he's a monster'
- 'I am 75 and it still hasn't stopped'
- 'My tormentor was there every day . . . waiting'
John Sharry advice: what can a parent do?