["St. Michael and the Dragon," Antonio del Pollaiolo, c. 1460-1470]
I strongly encourage those afflicted by demons to regularly attend Mass. But I know that it is difficult for them, especially for the fully possessed. When someone is possessed, there is a kind of interpenetration of the bodies of the possessed with demons. Thus, the possessed will often feel some of what the demons feel. So their lives will, at times, be a living hell-- literally.
For example, when placed in contact with anything holy, the possessed will typically say they feel excruciating pain. They will say that cold holy water burns. When looking at a crucifix, their eyes will feel like they are on "fire." When encountering a priest or a Catholic Church, they may feel intense hatred.
I asked "David," who formerly belonged to a Satanic cult and is now possessed, to do his best to attend Sunday Mass. He valiantly tries but has only managed to attend once every few months, if that. He said that when he is able to attend, "I can't say the prayers while I'm there or respond to them like everyone else does."
David added, "It's torture to be there, with all of the statues, and pictures that surround me." He went on, "All of the people and the priest praying is such a loud noise that it makes me so angry." And he concluded, "When they say the St. Michael prayer, I can hear the demons screaming. It's so horrible and frightening and painful."
I love the Church's sacramentals. They inspire and strengthen us. But they also serve an important apotropaic function: they are abhorrent to demons and help to cast them out. I noted especially David's comment about the St. Michael prayer: it frightens demons, causes them intense pain, and they scream in agony. I will be more diligent in using this prayer in our future exorcism sessions.