When we talk about sibling rivalry, we often envision young children squabbling or chasing each other, while their parents throw up their arms in exasperation. This is one aspect of sibling rivalry. In reality, sibling rivalry among adult siblings is also a very real and painful thing. Adult sibling rivalry can stem from many causes. One in particular can be when a sibling has a personality disorder. When this is the case, resolving long-standing issues presents extreme difficulty. Not only are