.Q: What do the other children in the family experience when they have a brother or sister who’s hostile or acts out chronically? James:
It’s traumatizing when something hurtful happens to you, and you can’t control it, you can’t stop it, you can’t predict how hurtful it’s going to be, and you can’t predict when or whether it’s going to happen. Children who grow up with a chronically defiant, oppositional sibling grow up in an environment of trauma.  They don’t know when they’re going to be verbally abused.  They don’t know when their things are going to be broken.  They don’t know when there’s going to be a major breakdown in the kitchen, and someone’s going to be restrained as they’re yelling and screaming.  Often, acting out kids target their siblings as sources of power. It makes them feel powerful to say mean or abusive things or to hurt their siblings. They like that feeling of power, so they do it over and over again. 

Several things happen in the mind of a child who lives with this kind of trauma.  First, the siblings of acting out kids become used to witnessing outbursts, and it has a negative effect on them in the long run.  These are people who grow up willing to accept higher levels of abuse in their marriages and their friendships.  They become desensitized to disrespect and abuse. They become numb to how it really feels to be called a name. They tolerate higher levels of disrespect and abuse in other areas of their life once they become adults.  Their ability to be assertive also diminishes.  READ Full Article