Demon Oppression
Demon spirits function in two ways, either by demon possession or demon oppression. It is not possible for a Believer to be demon possessed. Paul said:
"Know you not that you are the Temple of God (where the Holy Spirit abides), and that the Spirit of God dwells in you? (That makes the Born-Again Believer His permanent Home)" (1 Cor. 3:16).
Paul also said:
"You cannot drink the Cup of the Lord, and the cup of devils (if we are going to associate with demons, the Lord will not remain): you cannot be partakers of the Lord's Table (the Lord's Supper), and of the table of devils (that which the world offers)" (1 Cor. 10:21).
Demon possessed, no! Demon oppressed, yes! In fact, every single Christian who has ever lived has been oppressed by demon spirits at one time or the other. The Scripture also says concerning this:
"How God anointed Jesus of Nazareth with the Holy Spirit and with Power (as a Man, Christ needed the Holy Spirit, as we certainly do as well! in fact, everything He did was by the Power of the Spirit): Who went about doing good (everything He did was good), and healing all who were oppressed of the Devil (only Christ could do This, and Believers can do such only as Christ empowers them by the Spirit); for God was with Him (God is with us only as we are with Him)" (Acts 10:38).
Demon oppression can cause certain types of physical illnesses, emotional disturbances, nervous disorders, etc. When one is oppressed by demon spirits, it feels like there is a hundred pounds of weight on his shoulders. It is the major cause of depression. There's only on cure for this, and that is, once again, the Cross of Christ.
JSM