The Christmas cage match is under way: preteen siblings brawling for a preferred turkey part, angling for a sizable parcel under the tree and putting on the sulk if holiday chores aren't meted out evenly.
While sibling rivalry is a year-round tradition for those in their noxious adolescent years, the fights tend to intensify as families are quarantined together for days on end, hopped up on adrenalin, false expectations and vague guilt – the defining feelings of the Christmas season.
Now, American research suggests that chronic fights over personal space and equality in the household between adolescent siblings can trigger feelings of anxiety, depression and low-self esteem that stretch well into the new year.
Published Thursday in the journal Child Development, the longitudinal study involved 145 pairs of mostly white, middle-class siblings, and followed them over one year starting in either Grade 8, 10 or 12. The majority of pairs were two years apart and lived under the same roof. Researchers at the University of Missouri administered questionnaires, asking the siblings to describe their conflicts, noting frequency and how intense or "hot" the fights were. (The authors didn't ask "who started it," knowing full well they'd be getting two versions of the story.)
What they found was that sibling sparring at this age has two overarching themes, each with its own psychological fallout.
Conflicts about shared resources and responsibilities, or, as the authors put it, "equality and fairness," concern things like whose turn it is to empty the dishwasher, use the computer or ride in the front seat of the car. Arguments about invasion of personal space include entering a little brother's room without permission, or borrowing big sis's favourite Christmas sweater without asking. This invasion can also extend to psychological space, like loitering when your brother's cool friends come over.
The study then asked teens to report on their own levels of self-esteem, anxiety and depressed mood over the course of one year. Researchers found that siblings who fought over equality and fairness were more depressed a year later, while those who bickered about personal space were more anxious and had lower self-esteem a year later. (When it came to anxiety and low self-esteem, the most vulnerable were younger siblings and those dealing with opposite-sex siblings.) Problematically, teens who were more depressed and anxious then had more fights with their siblings a year later, perpetuating the cycle.
"It has to do with how they interpret these conflicts and what these issues mean to them," said Nicole Campione-Barr, the study's lead author and an assistant professor of psychological sciences at the University of Missouri.
With non-stop fights around equality and fairness, siblings can start believing "they're not getting their fair share of family resources," Campione-Barr said. "They might not feel they stack up nearly as highly against their sibling, who might be procuring more of those resources."
And with tussles over violations of personal space, preteens and teens are at their most sensitive: "These siblings are trying to individuate from the family and show themselves as their own person. If you have a sibling who's invading your space or trying to tag along when you have friends over, it's going to be harder to do that."
Campione-Barr hopes her findings might assist parents and psychologists support teens. Her main tip for parents? Don't pick sides: Previous research has shown that intervention can work if the squabblers are young, but by the time they reach adolescence, parental arbitration is largely useless, if not downright harmful. That's because tweens see any interference by parents – "no matter how hard you try to toe the line and stay right in the middle" – as unfair. Parental refereeing at this stage usually brings on more friction, and can erode trust and communication between siblings, Campione-Barr said.
She recommends mothers and fathers brace for battle by establishing household rules like knocking before entering a sibling's room. She also suggests a timer system for turns on video games, as well as a chore calender: "It's more, 'The calendar says you have to do the dishes tonight,' so the parent doesn't have to get in the middle. It's the calendar's fault."
Next, Campione-Barr plans to study what siblings do right during this fraught period of their lives, the key element being disclosure: At what point do you start telling your brother or sister things you wouldn't share with the 'rents, friends or anyone else?
"If we can set the stage for positive sibling relationships in adolescence right around the time they're about to go their separate ways, it can help later on down the road," said Campione-Barr.
"The sibling relationship is the most lifelong relationship that you're going to have."