Any good Christian has to believe in demonic possession. After all, Jesus was always casting out demons. If the Bible and Christianity is true, then Jesus couldn't have mistakenly viewed mental illness using the common superstition of possession. He would have known better. So they're real. That basis has been the support for dozens of demonic possession/exorcism movies, which mostly make good entertainment because, demonically possessed people look really freaking scary. They are great horror flicks. But ...