"Childhood bullies may pay a high price. Research shows that hostile children who mistrust others are much more likely than their peers to develop conditions such as diabetes and heart disease later in life. 'This clearly shows how psychology affects biology, even at younger ages,' Karen Matthews of the University of Pittsburgh tells USA Today. She studied 134 youngsters, ages 8 to 10 and 15 to 17, for three years, measuring how hostility levels related to body weight, unhealthy blood fats, insulin resistance, and high blood pressure. The more hostile the child, the more likely he was to develop at least two of these three physical problems. They were particularly likely to become overweight and develop insulin resistance. Mean kids may become overweight because they compensate for their lack of friends by eating too much, says Matthews. Although hostility appears to be about 30 percent genetic, parents can teach angry children to see the world differently. 'Teach kids that they're not being "dissed" by every wayward look, and that people's behavior isn't always directed against them.'"