USA TODAY (Michelle Healy) -- Being bullied by a sibling is not benign. It can significantly worsen a child's mental health.
Bullying and aggressive behavior by a sibling can be as damaging as bullying by a classmate, neighbor or other peer, finds a new study that links it to increased depression, anxiety and anger among victimized kids and teens.
And that association holds true for the various types of aggressive behavior studied, both mild and severe, from physical and psychological aggression to property victimization, researchers say.
Although peer bullying has increasingly become a recognized problem and the focus of preventive efforts, sibling bullying has historically been viewed as "benign and normal and even beneficial" for a child's social development and ability "to learn to handle aggression in other relationships," according to the study, in the July issue of the journal Pediatrics, published online today.
The study "shows that sibling aggression is linked to worse mental health (for the victim), and in some cases it's similar to what you find for peer aggression," says lead author Corinna Jenkins Tucker, an associate professor of family studies at the University of New Hampshire in Durham.
Tucker and colleagues analyzed data from The National Survey of Children's Exposure to Violence, focusing on nearly 3,600 kids 17 and under with at least one sibling living in the household. Kids were interviewed by phone about victimization in the past year. A parent or other adult caregiver answered on behalf of children under age 9.
Measures of mental health and four different types of victimization were assessed:
• Mild physical assault (hit, beaten or kicked without an object/weapon or resulting injury);
• Severe physical assault (hit, beaten or kicked with an object/weapon or causing injury);
• Property aggression (forcible theft, taking and not returning property; breaking or ruining property on purpose);
• Psychological aggression (feeling bad or scared because a sibling said mean things, called them names or excluded them).
"For all types of sibling aggression, we found that being the victim was linked to lower well-being for both children and adolescents," Tucker says.
Mental health distress scores were greater for children than for adolescents who experienced mild physical assault, but kids and teens were similarly affected by the other forms of sibling aggression, she says. And even kids who reported just one type of sibling aggression in the past year had higher distress scores than kids who reported none.
Just as parental violence and marital violence occurs in families, "sibling violence happens, as well," says Nicole Campione-Barr, director of the Family Relationships and Adolescent Development Lab at the University of Missouri. "This is something we really need to be aware of." She was not involved in the new study.
One sign that a sibling relationship is troubled: When aggressive interactions are "repeatedly being done in one direction," where one sibling "is consistently the victim and the other is constantly the perpetrator," she says. "That is akin to what we see in bullying."