Psychiatrists rarely diagnose narcissism in children due in large part to the fact that most symptoms are thought to present during adolescence and adulthood. Children typically have fantasies of unlimited power and ability, a key feature of narcissism outlined by the Diagnostic Statistical Manual of Mental Disorders IV (DSM-IV), but they also have personalities still in the making. There is a possibility that children will eventually grow out of their narcissistic behavior. However, studies have found that narcissism could manifest as a disorder regardless of age. Possible signs of narcissism in children include throwing tantrums when criticized, lack of responsibility for the consequences of an action, and resistance to attitude adjustment.
Several of the identified symptoms of narcissism in DSM-IV are related to having an abnormally inflated sense of greatness, both in the patient's perceived importance and abilities. In children, this can manifest as seeing other children below them. The narcissistic child believes that he is superior to his peers and will not hesitate to express this. He will exclude other children from his playgroup on the basis of less material wealth, poorer social status, and an inability to perform the same tasks at an adequate skill level. This also creates an inability to properly deal with criticism; the child believes that he is infallible and will react violently when told otherwise.
On the other hand, narcissism in children tends to magnify feelings of envy. Since the boy's perceived self-importance is higher than average, she will take it as an affront to her worth if she sees that others are better than him in some skills or have better things. This is often combined with antisocial behaviour, whereby the narcissistic child will often fight with children whom he sees as better than himself in order to establish his own superiority. In some children, this can manifest as a tendency to steal other's toys.
Narcissism in children can also inflate a child's sense of entitlement to unrealistic levels. A child with narcissism may resent being told what to do; she chooses not to acknowledge another person's authority simply because she thinks the other person is not as important as he is. In exchange for his perceived superiority, the narcissistic child will expect to be admired by the people around him, creating a pathological need to be the center of attention. These unrealistic expectations can lead to withdrawal from people who don't reinforce them, a key trait of narcissism in children.