[quote=Paris Blues]I was flipping through a Catholic book catalog I got in the mail a few months ago and I came across a book listed in it that was about like what’s the difference of being possesed by a demon or if pyschological ill or something like that and that now gave me the question:
how do you know if you have a demon or if you’re just mentally ill?
Those conditions pointed out by Rand are certain indicators of possession that Catholic exorcists use to judge whether or not to perform an exorcism, but they are not the only tests. Possession can occur with much more subtle symptoms. Ideally, someone with one of the charisms listed in 1 Cor is present and can tell whether or not a demon is responsible, that’s the gift of discerning of spirits. In Father Amorth’s book, he describes how his mentor, Father Candido, had that gift and would just lay his hand on an individuals head and he could tell whether or not a demon was present.
Jesus frequently encountered demons in the course of praying for people’s healing. As He laid hands on them to pray, a demon would come out in shrieks. There’s nothing in scripture that says any of these were necessarily known to be possessed ahead of time. Disease can be from a demonic manifestation, a psychological manifestation or a physiologic cause.
Personally, since I don’t have the gift of discerning of spirits, I always look for solutions in the reverse order - try to cure it medically, then try looking for emotional/stress causes, and if all else fails, pray for deliverance. A disease caused by a demon does not necessarily mean full possession, and thus wouldn’t trip an exorcist’s tests. Sometimes a simple prayer of deliverance can accomplish much.