Parental narcissism affects every aspect of a child's development, including relationships with siblings. In some cases, the siblings might not be as close to each other as they otherwise would be, and in others, one child might show narcissistic traits modeled after those of the parent while the other learns to eclipse his own personality to accommodate his narcissistic family members.
Narcissism is a personality disorder defined by low self-esteem and a deep fear of being judged, criticized and rejected by others. To prevent this from happening, the narcissist adopts an exaggerated persona of being better, smarter or more capable than other people, combined with a number of manipulative behaviors designed to control how others feel so they don't judge and reject the narcissist. According to psychologist Alan Rappaport in an article for "The Therapist," a narcissistic parent cannot treat his children as independent people with their own feelings and dreams in life. Instead they become extensions of his own neediness.
Intense conflict among siblings is more likely when one of the parents is narcissistic. According to a 2011 study published in the "Journal of Psychology," parental narcissism is strongly correlated with sibling conflict, especially when combined with favoritism. Narcissists typically favor one child over the other, making one sibling a scapegoat and target of criticism. According to a 2011 article in "Psychology Today," siblings who grow up in this kind of family are usually not emotionally close.
Favored Child and Scapegoat
While one sibling might be treated as the golden child and the other as the scapegoat, the circumstance is equally damaging to both siblings. The scapegoat receives constant criticism and harshness from the narcissistic parent, while the favored child receives the message that she is only valued for doing whatever makes the narcissistic parent feel better about herself. For example, the favored child might be pressured to go into the same career as the narcissistic parent and might be rejected if she doesn't choose to do so, according to Rappaport's article.
Children growing up with a narcissistic parent find coping strategies to help them get by, and these strategies can affect their relationship with their siblings. According to Rappaport, some children cope by complying with the narcissistic parent and disregarding their own needs, a condition Rappaport calls co-narcissism. Some cope by rebelling against the parent. Some cope by identifying with and imitating the narcissistic parent, so that they end up becoming narcissists as well. If one sibling copes by rebelling and another by complying, they might have a hard time relating to each other because the compliant child sees the rebellious child as selfish. If one sibling copes by complying and the other by identifying, the compliant child can end up being totally focused on the needs of his narcissistic sibling and parent, never thinking about his own needs. This pattern can continue into the child's adult relationships.