I hate headlines like this. What it should have said was "Facebook OVERuse..." Which is just as true of any number of things. For example, students who check Facebook during a 15-minute period when they're supposed to be studying get lower grades. No, really?
You cannot make a non polarizing comment about this topic but i think it's a good thing that this research is done. Facebook or social networking general is affecting the life of a lot of people, there is definitely change in peoples personality.
you're right. though facebook profiles owners cannot be younger than 13, there is about 1,5-2 million teens registered. we should do something!