(Newser) – If you keep telling your children that they are special, you may end up with kids that go around acting like they're better than everybody else, according to a new study. In what researchers say is the first study to look into how narcissism develops over time, children between the ages of 7 and 12 were interviewed over an 18-month period and the results showed that kids described by their parents as more special than others were more likely to show signs of narcissism later on, Ohio State University says in a press release. But while the "overvalued" kids developed narcissistic tendencies, it was the ones whose parents showed more emotional warmth who developed healthy levels of self-esteem, according to the study published in the Proceedings of the National Academy of Sciences.

"Self-esteem basically means you're a person of worth equal with other people," study co-author Brad Bushman tells NPR. "Narcissism means you think you're better than other people." Children with healthy self-esteem, he says, agreed with statements like "Some kids like the kind of person they are," while narcissists agreed with statements like "Kids like me deserve something extra." Bushman, a father of three, says his research has changed his own parenting style. "I used to think my children should be treated like they were extra-special. I'm careful not to do that now," he says. "It is important to express warmth to your children because that may promote self-esteem, but overvaluing them may promote higher narcissism," which can lead to higher levels of aggression and violence. (Another recent study found that a surprising number of 2-year-olds may be drinking coffee.)

