So she had been locked in an attic from the age of about 9 or a bit younger. And she already at that point had a mental illness. By keeping her locked in an attic, probably made her go delusional just seeing one room for so long. Her mother did let her out from time to time, but I didn't seem like enough. But I do understand why her mother didn't send her to an institution, since they would've hurt her there.

I think Cruella being evil is nobody's fault. It's a difficult situation.

I had to think for a while on this one, because as you said it is a difficult situation. Keeping her locked in an attic certainly didn't help her get better, and it did give her more of a reason to spiral out of control, but in the end I don't think it made her any worse. She was a sociopath from the start, and she loved killing people, and that's what she still was after escaping the attic. That being said, I'm certainly no expert in psychology, so I could be way off base.

I may have worded the question wrong, but if you think it gave her more reason to spiral out of control then I would say that would be a "yes" pick. Like I said, it's difficult to word what I actually mean.

Isolation is never a good thing. Put a perfectly 'normal' person in isolation and they can go nuts; just look a the feral children. Of course Cruella's wasn't that extreme but it's still no good to do.