Years ago, my 7-year-old brother and I played on the same little league team. Given our young ages, the coaches refrained from keeping score or announcing individual stats, and at the end of the season everyone got a trophy. On the field, everyone was the winner. But in the car and around the dinner table, it was an entirely different story. I loved the game and played hard, while my brother preferred to study the dandelions in the outfield. And this difference seeded a host of stories in which I played the hero and my brother played the fool. I announced every play like a personal highlight reel, punctuated by nonstop digs at my brother, whom I denounced for being lazy and uncoordinated.

Today, I see this as the beginning of a prolonged competitive game of one-upmanship and sibling rivalry. My brother and I competed with each other over everything: who was the best student, athlete, musician, secret-keeper? For the most part, it was in the spirit of healthy competition, spurring us both on to be our best. But in recent years, with the eyes of a mental health professional, I have begun to wonder if there were times when our rivalry crossed the line into cruelty and bullying. Where is that line? And what happens when sibling rivalry goes too far?

Healthy sibling rivalry is based on competition for praise and attention, usually from parents or other adult figures in a child's life. It can take the form of competitiveness over sports, activities, or school work, all for prized recognition from parents and other important adults - made more valuable if bestowed in front of siblings. Typically, the winners and losers vary, and the competition remains evenly matched. But when the balance of power between siblings becomes one-sided and one child begins taking pleasure in creating "contests" to intentionally cause psychological or physical suffering to another, rivalry has crossed the line into abuse.

Abusive sibling rivalry can take many forms, from physical "wrestling" to cause injury, to teasing and telling jokes intended to make a sibling cry. In a 2015 study in The Professional Counselor, researchers from Clemson University report as many as 80% of children will experience intentional violence from a sibling, making sibling abuse the most common type of child abuse. Children who are abused by siblings may exhibit signs such as avoidance of the abusing sibling, alterations in sleeping and eating patterns, increased anxiety, withdrawal from friends and family, and depressed mood.

Unlike healthy sibling rivalry, which draws focus to the child him/herself for the purpose of gaining praise or positive attention, unhealthy rivalry is constant and is directed toward the goal of inflicting pain on a sibling. An example would be one child "accidentally" tripping his or her sibling in order to win a race as opposed to a child fairly winning a race and boasting to anyone who will listen. In one instance a child is intentionally inflicting harm, while in the other any harm is an accidental byproduct of being proud and excited. While not all instances of unhealthy sibling rivalry are as clean-cut, parents should look for a pattern of constant arguing and nastiness, as opposed to occasional occurrences, as a possible sign of unhealthy rivalry spiraling toward abuse. If this is occurring, then parents can no longer "let the kids work it out" or dismiss the rivalry as "kids being kids," but must intervene when conflicts occur.

Stepping in during the early stages of hostile sibling rivalry is the best way to prevent rivalry spiraling into abuse. Early, proactive interventions might include the following:

-*- Have children help create family rules and consequences. This can instill a sense of empowerment in the children and also ensure that they understand behavioral limits.

-*- Be consistent in enforcing rules. This gives children a sense of security in knowing what is and is not allowed, and reduces temptation to "get away with it."

-*- Monitor. When hostile rivalry is suspected, parents are encouraged to consistently monitor sibling interactions to be sure conflicts are being solved in a healthy and productive manner.

-*- Demonstrate appropriate interactions. Children copy what they see and hear, and parents are the best people to model appropriate problem-solving, "fair-fighting," and apologies.

-*- Reward children for following the rules and using appropriate conflict resolution skills.

-*- Make positive time for each child, individually. Ensuring siblings have healthy relationships when they are young takes awareness and effort, but also paves the road for strong and supportive relationships later in life. It's an investment worth making.

Marissa Kirby is a graduate student clinician in the Mental Health Counseling program at Becker College. She provides counseling services to adults, children, couples and families through the Counselor Training Clinic (CTC) at Becker College in Leicester. Visit mhcclinic.becker.edu for more information about low-cost, professional counseling services at the CTC.