with Jason. It does sound to me like she might just be spoiled. It is hard to say exactly though ,since we aren't able to see her and also, I'm not a professional in this matter.

I can imagine how frustrated and tired your mother must have been. Kids like that take a lot of energy out of adults!
In addition to ADHD- your family might want to look into Asperger's Syndrome-- there are mild cases-- in which a child is functional-- just out of step socially--they're rowdy, can't seem to follow rules, say and do inappropriate things-- just a thought!

Anyway-- good luck with your niece!

Mandy