And maybe a good metaphor for difficult children all together. Personality disorders have some genetic and biological factors but are considered heavily environmental. That of course makes you wonder, how kids from good and loving families can have them too. Of course at times it can be something that happened that even parents don't know or there have been major personality clashes between parents and child, but sometimes it is just a mystery. I read a nice metaphor to explain that. it was about flowers and how people are born different like flowers. some are born to be dandelions. Even in the most difficult environments they flourish. They find a way to grow even from a small crack of concrete and almost nothing can put them down. others are born rare and delicate orchid that even in most delicate care have a high chance of failing to thrive. Everything have to be just right to make the flower, but when they do, beautiful and rare they are. And it is just about luck and genetics, if you give birth, or adopt, a dandelion or an orchid. As a mother of one orchid and one dandelion I found this very true metaphor.