Exorcism is (1) the act of driving out, or warding off, demons, or evil spirits, from persons, places, or things, which are believed to be possessed or infested by them, or are liable to become victims or instruments of their malice; (2) the means employed for this purpose, especially the solemn and authoritative adjuration of the demon, in the name of God, or any of the higher power in which he is subject.

...more

I believe some ppl can be processed by the demons or evil spirits. And an Exorcism needs to be done. But those demonic processions are very, very rare indeed. The movie "The Exorcist" I believed was based on actual events. The person who was processed was a boy. "The Exorcist" was very well made and it does at times gives you the creeps.

Your thoughts on the subject (if any). Enlighten and Indulge me!