Enmeshment is a dysfunctional state where a two or more people have porous and indistinguishable boundaries. Enmeshment can occur between a parent or child, whole families, or adult couples. This article will be talking about enmeshment between a narcissistic mother and her son. The narcissistic parent could become enmeshed with her daughter or all her offspring, though. The same goes for a narcissistic father.
Since the boundaries between two enmeshed people are permeable, they tend to catch each others emotions. If the narcissistic parent becomes angry at a store clerk who slighted her by waiting on another customer first, her son will grow angry as well.
Emotions are a complicated thing for those in an enmeshed relationships. Unable to tell the difference between each others emotions, each member in the relationship will have times when they feel they need to be rescued from their emotions by the other person. Similarly, they’ll each have time when they feel they have to rescue the other person from their emotions.
Those in an enmeshed relationship come to depend the other enmeshed person for their identity. They become so lost that they lose, or fail to develop, their sense of self.
An enmeshed person depends on the person their enmeshed with for their self-worth. Since narcissists emotionally abuse their children, their enmeshed offspring often have low self-esteem.

http://narcissismschild.com/2015/03/16/the-consequences-of-enmeshment/