Can Christians be demon possessed?

I can only answer for my specific Christian denomination: the Church of Jesus Christ of Latter-day Saints. We do not believe in demonic possession in the typical sense (exorcisms, etc.). What we believe is that someone can willingly give themselves to Satan by not following the commandments and other guidelines that Christ has set out for us.

The best analogy I can think of to help explain this is a thread versus a rope versus a chain. You can snap a thread relatively easily. A rope is something you have to cut. A chain is impossible to cut because it’s made of metal. The first time someone sins, they have a thread. The threads collect the longer someone sins. Often, by the time someone realizes what’s going on, they have something similar to a spiritual chain.