This leads me to raise another question, can a solid devout Catholic in the state of grace be possessed? The exorcists that I have seen comment on this say that it is impossible.
Yes, I've heard that too, but I've also heard sometimes, but it's very unusual? If someone were to put a curse on a devout Catholic, I believe it is possible. At least this is what Fr. Fortea has to say in the book,
Interview With An Exorcist. Remeber, satan can possess the body, but the soul isn't his until after death, unless someone has truly given themselves over completely.
We know that many saints were bothered by the devil, St. Padre Pio, St. John Vianney, many others.
Fr. Fortea also said that someone in a state of grace can be possessed through no fault of their own, if they are to become a victim soul. That would be Emily Rose. Blessed Alexandrina de Balazar I believe was possessed for a time, in reparation for souls. She suffered very much. But, I can't find anything online about the possession. Still I have a book about her life somewhere (put out by TAN), so I'll double check it if I can put my finger on it...(where is it?)