Improving sibling relationships

Eight in 10 children in the United States are growing up with a sibling—more than the number of kids living with a father. Yet sibling relationships earn a fraction of the attention that family studies researchers have cast on other close relationships. But ignoring the role of brothers and sisters in children’s growth and well-being is a mistake, said Susan McHale, PhD, a professor of human development and family studies at Penn State University. Over the course of childhood, she and her colleagues have found, children spend more out-of-school time with their siblings than with anyone else, including parents and friends. And over a lifetime, siblings are often the people with whom an individual will ultimately share the most years. “Siblings are most people’s longest-lasting relationships—from early in childhood through old age. This means they can understand you in ways other people can’t,” she said.

In the process, brothers and sisters affect each other directly and indirectly, said Shawn Whiteman, PhD, a professor of human development and family studies at Utah State University. On one hand, siblings support and learn from one another. On the other, they compete for parental attention and can introduce one another to risky behaviors, including substance use and sex. “The sibling relationship has the ability to uniquely shape a child’s behavior, adjustment, and ­well-being, for better and worse,” Whiteman said.

Well into adulthood, siblings keep influencing one another’s mental health and well-being. Warm sibling relationships—those with more affection and intimacy and less conflict—are a source of material and emotional support, with the power to protect against loneliness and depression. But research shows that fraught sibling relations are associated with a host of negative outcomes in adulthood, including depressive symptoms and substance use.

Add to that, sibling relationships are rarely clear-cut, which can make them especially tricky to navigate. “We often find that siblings who have intense conflict are also intensely loyal and loving to one another,” McHale said.

Despite the complexity of sibling relationships, psychologists are fleshing out the ways in which they matter. In childhood, these relationships have significant influence on development, in some cases greater than the influence of parents or peers. Sibling conflict, however, can be stressful for entire families—and may contribute to depression and loneliness among adults. Fortunately, the research is also pointing toward ways to help siblings get along.

Sibling relationships in childhood

Though research on siblings has lagged, these relationships are gaining more attention as psychologists find increasing evidence of their importance for development and well-being, said Laurie Kramer, PhD, a clinical psychologist at Northeastern University who studies the mechanisms by which young children can develop positive relationships with their siblings. “We’re learning more and more about their significance and how siblings help one another—and create conflict—across the life span.”

From early childhood, siblings are important teachers. They model how to behave at home and in the world and can offer practical advice on everything from math homework to asking a crush on a date. “Siblings often have a better sense of what you’re experiencing with peers or with parts of your world that parents don’t have access to or don’t see in the same way. That shared perspective is one of the facets that makes sibling relationships so valuable for child development,” Kramer said. And that shared experience continues to be important far into the future. “No one else will know what it was like growing up with your parents in your household, and that sense of being understood by another person can be incredibly powerful,” she added.

Sibling warmth and support in childhood has been linked to a number of positive outcomes, including peer acceptance and social competence, academic engagement and educational attainment, and intimate relationships in adolescence and young adulthood, as McHale and colleagues described in a review of sibling dynamics in childhood. Warm sibling relationships can also help buffer against the negative effects of stressful life events such as bullying or parental hostility, they found (Clinical Child and Family Psychology Reviewopens in new window,Vol. 15, No. 1, 2012).

Children can also learn bad habits from their brothers and sisters. “Siblings can shape risky behaviors during adolescence,” said Whiteman, who is studying how siblings influence substance use in adolescence. He’s found, for instance, that older siblings often introduce younger siblings to alcohol directly by providing it or by drinking with them. But older siblings also influence younger siblings’ alcohol use indirectly by shaping their expectations about drinking (Addictive Behaviorsopens in new window,Vol. 53, 2016). “Having an older brother or sister who uses substances makes you more likely to use them. And if you look up to them, you’re much more likely to engage in substance use,” he said.

Sibling conflict can also lead to negative consequences. While minor squabbles can help children learn to solve problems and navigate conflict, high levels of conflict and aggression between siblings can have lasting effects on a child’s mental health.

In a longitudinal study of U.S. adolescents, McHale and colleagues studied sibling relational aggression—nonphysical aggression such as excluding or belittling a sibling. They found sibling relational aggression was associated with depression, low self-worth, and participation in risky behaviors. But those negative outcomes differ somewhat in boys versus girls, older versus younger siblings, and siblings in mixed-gender versus ­same-gender pairs. In other words, there’s more work to be done to fully understand the complex ways siblings can harm one another through mean behavior, McHale said (Journal of Youth and Adolescenceopens in new window,Vol. 47, No. 10, 2018).

All told, sibling interactions and relationships deserve much more attention from parents, educators, mental health professionals, and researchers, said Whiteman. “Sibling relationships predict youth outcomes above and beyond the influence of parents and peers.”

Healthy adult relationships

Sibling relationships remain important well into the adult years. Though siblings may interact less frequently as they get older, some research suggests that they may start getting along better in young adulthood. Whiteman found that siblings report less conflict over the course of young adulthood (Journal of Family Psychologyopens in new window,Vol. 32, No. 3, 2018). He also found that while young adults reported communicating less frequently with siblings after leaving home, they considered those talks more meaningful and felt they better understood their siblings in emerging adulthood (Journal of Social and Personal Relationshipsopens in new window,Vol. 36, No. 8, 2019). Sibling support also has tangible benefits in early adulthood. A longitudinal study of university students found that when pursuing personal goals, sibling support is as advantageous as support from parents and peers (Audet, É. C., et al., Family Relationsopens in new window,Vol. 70, No. 5, 2021).

Having close sibling relationships in childhood continues to impact well-being well into middle age. Harvard University psychiatrist Robert Waldinger, MD, and colleagues explored the influence of siblings using data from the Harvard Study of Adult Development, which has followed male subjects since 1938. They found participants who reported poorer relationships with siblings at age 18 or 19 had a greater likelihood of major depression and use of mood-altering drugs by age 50. That pattern held even after adjusting for the quality of the participants’ relationship with parents (The American Journal of Psychiatryopens in new window,Vol. 164, No. 6, 2007).

Siblings keep influencing one another as they age, said Megan Gilligan, PhD, an associate professor of human development and family studies at Iowa State University who researches sibling relationships in older adults. And the quality of those relationships continues to have implications for well-being. In a study of older adult siblings, Gilligan found participants generally reported high levels of warmth and low levels of conflict. Sister-sister pairs were especially likely to report warm relationships. Warm sibling relationships, in turn, seemed to protect against loneliness. However, older adults who reported more sibling conflict and parental favoritism in adulthood were more likely to experience symptoms of depression, anxiety, hostility, and loneliness (Journal of Family Psychologyopens in new window,Vol. 34, No. 2, 2020). “Siblings are really influential in mental health, well beyond childhood and adolescence,” she said.

How to build strong relationships

Parents can help improve these critical relationships from the beginning. According to family researchers, one of the most important things parents can do early on is to avoid behavior that can be seen as favoring one child over another. “Children are keen observers of how they are treated differently from their brothers or sisters,” Whiteman said. “The perception that you’re not the favored one is linked to poor adjustment and impacts the quality of relationships with your parents and your siblings.”

“Differential parental treatment,” as researchers describe the phenomenon, can affect every child in the family and can continue to drive a wedge well into adulthood, Gilligan said. “The presence of favoritism, even if you’re the favored one, can cause competition and conflict. Perceptions of favoritism also exacerbate conflict during times of stress, such as when caring for parents later in life,” she said.

To avoid this major source of conflict, parents should regularly consider if they are creating a fair environment, Whiteman said. Parents should avoid comparing siblings or setting them up to compete with one another. And hard as it may be, they should try not to take sides when siblings argue. Parents do sometimes need to treat kids differently. “But it has to be fair. Justice is very important for children,” he said. If parents tell their daughter she can’t stay out as late as her brother but don’t give an explanation, she might see it as favoritism. Instead, they should explain that she has an earlier curfew because she’s younger, and she’ll probably recognize the argument as just.

Parents can also foster close sibling relationships by promoting healthy relationships with other friends and family members. Kramer followed sibling pairs for 13 years, beginning before the birth of the second child, and looked at a number of different factors to predict which siblings would have the most positive relationships. She found that preschoolers who had a positive relationship with a best friend before their sibling was born were more likely to have a good relationship with their brother or sister. “Best friendships were the most predictive thing—even more important than the quality of the older child’s relationship with their mother,” she said.

Parents should also proactively coach young children on how to get along, according to psychologists. When siblings are left to sort out problems on their own, they’re likely to continue fighting—and that unresolved conflict can intensify, potentially leading to sibling bullying or aggression. Kramer’s research indicates that parents can help their children develop skills to manage sibling conflict by teaching them to express their points of view in a disagreement and actively solving problems with their kids to help them find solutions to their arguments (Kramer, L., et al., in Fiese, B. H., et al. [Eds.], APA Handbook of Contemporary Family Psychology: Foundations, Methods, and Contemporary Issues Across the Lifespanopens in new window, 2019). Once they’re sure the kids have the skills to manage conflict, then parents can begin to step back to let them solve problems on their own.

“It’s important to put intentional strategies into place. When children lacking these skills are left to their own devices, they flounder,” Kramer said. “Every day, parents have so many opportunities to help children develop a more positive relationship with one another.”

To help with that goal, Kramer and colleagues created the More Fun with Sisters and Brothersopens in new window program, a free online intervention for families with two children between the ages of 4 and 8. The intervention teaches parents strategies to help their children develop social and emotional competencies, such as accepting or appropriately declining invitations to play, regulating emotions, and managing conflict. A study of the intervention found children whose families participated had greater emotional regulation and better sibling relationship quality at the end of the monthlong intervention than those in a wait list control group (Journal of Family Psychologyopens in new window, Vol. 29, No. 3, 2015). What’s more, the study found the intervention also relieved mothers’ stress and depression by improving family harmony.

McHale and her colleagues—Penn State psychologist Mark Feinberg, PhD; Arizona State researcher Kimberly Updegraff, PhD; and Harvard University researcher Adriana ­Umaña-Taylor PhD—have created and tested the Siblings Are Special program, a ­12-session after-school intervention for siblings in elementary school. One randomized controlled trial found the program enhanced positive sibling relationships and improved children’s self-control, social competence, and even academic performance (Journal of Adolescent Healthopens in new window,Vol. 53, No. 2, 2013). A second trial involving low-income Latino families also found positive effects, including improvements in sibling relationships, parent-child relationships, and older siblings’ emotional efficacy (Journal of Family Psychologyopens in new window,Vol. 30, No. 5, 2016). In both cases, the intervention also reduced depressive symptoms in mothers. “That’s not surprising when you consider that sibling conflict is one of parents’ largest everyday stressors,” McHale said.

Resolving conflicts isn’t the only way parents can foster a close relationship between siblings. They can set up opportunities for kids to spend time together by doing shared family activities such as playing sports or board games and by making sure today’s overscheduled children actually have time to engage with family. And it helps to let siblings know that parents value their relationship with one another. “Simple messages of praise—such as, ‘It warms my heart when I see you two playing together’—can give children the message that sustaining a positive sibling relationship is important and valued by parents,” Kramer said.

Rewriting family history

Sibling relationships naturally change over the course of a lifetime. Transition points such as leaving home, getting married, having kids, and dealing with parents’ divorce or death offer natural opportunities for siblings to reevaluate and reinvest in these relationships, Whiteman said—whether by coming together or drifting apart. “Whenever there is a transition, it offers an opportunity for change,” he said.

Psychotherapists should help patients explore how these influential relationships affect them in ways both positive and negative. “In practice, we tend to focus on individuals’ relationships with their parents. We often overlook the very formative contributions that siblings have on our ­well-being and growth,” Kramer said. But there are important reasons not to overlook the influence of brothers and sisters.

When spending time with siblings, “we tend to fall back into the well-worn grooves of our family roles,” said Eileen Kennedy-Moore, PhD, a clinical psychologist in Princeton, New Jersey, and author of Kid Confidence: Help Your Child Make Friends, Build Resilience, and Develop Real Self-Esteemopens in new window (New Harbinger Publications, 2019). Even as adults, siblings often tease one another and push each other’s buttons. At the same time, they can become frustrated by patterns that seem to play out again and again—such as older siblings feeling like their younger siblings don’t pitch in to help as often as they should, and younger siblings bristling at unsolicited advice from their big brother or sister. Clinicians can help patients recognize and change these patterns.

To reset the dynamic, Kennedy-Moore recommends helping patients to recognize the role they play in these patterns and consider their siblings’ behavior through a new lens. “Our image of our siblings can be out of date. Just as we want our siblings to recognize we’ve changed [since childhood], we also have to watch our own assumptions about what they’re like,” she said. As with any relationship, sibling relationships benefit from clear communication and good boundaries—skills that psychotherapists can help patients develop.

And though sibling relationships may not be top of mind in a typical therapy session, they are worth asking about and addressing, Kennedy-Moore added. “Sibling relationships are often the longest relationships of our lives, and are at least as important as the parent-child relationship,” she said. “We can’t redo the past, but we can choose to move forward with our siblings in different ways.”