>>18092210 (OP)
Like with almost everything else, the difference between protestants and catholics on this issue comes down to authority and ritual. A lot of protestants believe that for a true believer it's nearly impossible to become possessed because the act of invoking the authority of Christ creates an environment that is intolerable to any demonic force.
Catholics believe that you need a formal church representative to do things in a certain way and that the average lay person can't help themselves against the power of evil.
I am a protestant myself so I tend to believe in the former view. I've never experienced anything that was for sure supernatural, but the closest I've come to that was when I was a teenager. I had started reading the bible and one particular night I read the Book of Revelation. After I fell asleep I experienced sleep paralysis for the first and only time of my life. After a couple minutes I was able to break it by thinking very clearly something along the lines of rebuking evil in the name of Jesus.