For better and for worse, siblings affect each other through both friendship and rivalry that can last a lifetime.

By following a program that teaches elementary-age brothers and sisters how to get along, a new study finds that parents can emphasize the positives. The payoff is a boost in their kids' future health and happiness.

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The study looked at results from a new prevention program called SIBlings Are Special, which was developed by researches at Penn State. As part of the study, sibling pairs participated in 12 after-school sessions that included games, role-playing activities, art activities and discussions. The goal was to teach brothers and sisters about positive ways to communicate, problem solving and working together as a team.

Over the course of the program, kids also showed parents what they had been learning during three "family fun nights." Each pair of siblings included a fifth grader and a brother or sister in the second, third or fourth grade.

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Compared to pairs of siblings who were assigned to a control group, the kids who went through SIBS demonstrated better self-control and social confidence, the researchers reported in the Journal of Adolescent Health. They did better in school and had fewer depressive symptoms.

Instead of settling fights between siblings, the authors suggest, parents can help their kids by giving them the tools to calmly discuss their disagreements and come up with their own solutions.

"We think that by encouraging siblings to feel like they're part of a team, and by giving them tools to discuss and resolve issues, parents can help their kids develop more positive relationships with each other, which can benefit everyone in the family," said Mark Feinberg of Penn State's Prevention Research Center for the Promotion of Human Development, in a press release.

"When siblings come up with their own solutions, they may be more likely to use those solutions again in the future," he added. "It's an investment in reducing your own stress and enhancing your children's well-being for the future."

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