Originally Posted by best deatheater

I don't think she was overlooked by her parents, I think quite the reverse. I think she was pampered and embraced her parent's pureblood madness. She always has that smug, haughty nature about her, even on trial she sat on the chair as if it was a throne. I think she like most tyrannical upper-class people in history treated people below her rank with disdain and hatred. Poor people and people related to muggleborns would be disgusting to her and someone like Voldemort, who took muggle persecution to an extreme, would be a sort of heroic figure. So no doubt he bent her mind slightly by manipulation and showing her fantastical things.
Azkaban might have done some damage as well. But I know the idea for Bellatrix and kids comes across strongly in HBP Spinners end. I'm just glad she doesn't have kids.