Almost 3,600 children from the Avon Longitudinal Study of Parents and Children, completed a questionnaire on sibling bullying at 12 years old and then subsequently filled out a questionnaire when they were 18.
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.
“Bullying by siblings has been until recently widely ignored as a trauma that may lead to serious mental health problems such as psychotic disorder,” said lead author Professor Wolke, from Warwick’s Department of Psychology.
“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.”
The researchers concluded that parents and health professionals should be made aware of the mental health consequences that sibling bullying may have.
Professor Claire Hughes, a developmental psychologist at the Centre for Family Research, Cambridge University, and director of studies at Newnham College, said sibling violence is the most common form of violence in the family. Oftentimes, this can be normal, but she said working out the tipping point will be on a lot of parents’ minds.
Hughes said it’s important for parents to take into account that sibling relationships, unlike other relationships between kids, are involuntary, telling HuffPost UK: “You don’t get to choose siblings, you spend 24/7 with them so it’s very easy to see how kids wind each other up. There is also an intense familiarity there.”
Squabbling and clashes of personality are common among brothers and sisters, so how can parents tell when sibling rivalry goes too far and crosses the line into bullying?
1. Monitor whether they show closeness as well as rivalry.
“Kids show a lot of individual differences in different dimensions,” said Professor Hughes. “So just because there is sibling rivalry doesn’t mean they don’t show a lot of closeness, too.”
She said parents should monitor whether there is a lot of rivalry and not much else, because if that’s the case, there’s not a lot that might redeem the relationship, so things might be a bit more serious.
However, if there are situations where your children do get on, show each other love and enjoy each other’s company, that shows you their relationship isn’t solely based on bickering.
2. See whether the rivalry is sustained and escalates over time.
A flag point for parents will be to see whether the conflict between children is sustained or even escalates over time, said Professor Hughes, as this has been shown to be related to bullying.
Episodes of rivalry, she said, are not a problem, but a question parents should ask is have they been like this for years and has it got any better?
This fits in with the study, where the authors found that those involved in sibling bulling more frequently (several times a week or month) were two to three times more likely to develop a psychotic disorder than other kids.
3. Try to work out the causes.
Hughes said there are a lot of normative causes of rivalry, but there may be more worrying causes including family issues, such as being associated with parental favouritism. “This is relatively common for one kid to be scapegoated and can lead to all sorts of dynamics going wrong,” she said.
“Know what extent the children’s behaviour is mirroring other things going on in the family.”
4. Talk to both the children when the situation arises.
One way to know whether your kids’ relationship is verging on bullying is to speak to them both about the situation of rivalry as soon as it arises. “All bullying should be taken seriously,” said Jeremy Todd, CEO of Family Lives.
“The only way to understand the impact is talking to both the children. A lot of families get used to the different behaviour of their children and normalise it (‘He always overreacts’ or ‘He’s a bit sensitive’). We recognise this and we have generic responses, but we should question what we are really listening to.”
Todd said every time there is a sibling disagreement, the parent should ask the children to stop, sit down and talk about what happened: “We should encourage parents to clarify the argument and get an explanation that feels sufficient,” he added.
This also includes speaking to the children - the victim and the perpetrator - separately outside of that initial conversation to understand how they are feeling and the impact of what happened.
“Parents need to say: if it is a big deal there will be a consequences if it happens again,” he added. “Ultimately, children have to learn to find a way to get on.”
What should a parent do if they are worried?
“Parents should model how to give in gracefully to an argument and they should also recognise the involuntary nature of the relationship,“Professor Hughes explained.
“Give your children praise and accentuate the positives when they are kind to each other. If that doesn’t work, give them a bit of space and monitor whether it is happening in any other of their peer relationships before reaching out for help.”
Todd added that parents can speak to other families on the Family Lives forum to learn from others going through similar issues.