It is very reassuring to read your thread and know I'm not alone. I feel the same way about my mother. She's not aggressive as such but she's a different person to the one I thought I knew. She's selfish, passive aggressive, and egocentric. She does not accept her diagnosis, which somehow makes it worse. I know its the dementia but where I struggle is that as she is intelligent and articulate, its sometimes difficult to separate it out. I question whether I never really knew her at all and this was the person she now cannot hide. Then feel horribly guilty that I could possibly think those thoughts and so the vicious circle continues. It is a constant rollercoaster and a cruel disease.