It sounds like you are describing my ADD-with-anxiety daughter, who is now 20. She never had much trouble MAKING friends, but when whenever a transition point came (summer camp ended, a move from middle to high school or high school to college) she always seems to dump the old social group cold, sometimes on a pretext of a mild squabble. But any time there is any tension, she is quite a bridge-burner. Her psychiatrist believes it’s partly the impulsivity of ADD, and partly the anxiety that makes her lash out, out of proportion to a situation. Then the ADD-typical inability to apologize or admit wrongdoing seals the deal, and she is forced to realize she is friendless again – until she finds a new situation where no one heard of her past behavior. I am hoping that maturity will help, because talking about it with her only angers her.