I think demonic possession is generally thought of as being like the Hollywood films, but the priests I talked to about it feel it is more subtle and more like a person being influenced by a dark energy than what was portrayed in the Movies. My W, also someone who considers herself a scientific thinker, recalled an encounter with a spirit where her body became warm and pressure prevented her from moving. Keep in mind she is a physician so supernatural isn't her default. My question is could it be possible that she was infected, for lack of a better word, by spirit or dark energy and then when she was physically and spiritually weak the force/entity took control of her?
I talked to several priests, one a very well educated professor and scientist, and I was told that it is difficult to tell as the personality change could be due to a number of factors, but the immoral behavior, rejection of religion, and embracing new secular values was disturbing. W also became a big believer in astrology which is not condoned in the Catholic Church. I don't think a Hollywood like demon is the issue, but is a evil influence a factor. Interestingly enough the kids now call her the demon sometimes. If the eyes mirror the soul there is evil in her, but I'm not certain about the what and why.