The was a show on Discovery I saw years ago... It's called "A Haunting". They basically reinact events that happen. One of them, this family moved to a new house and their kid started acting weird.
They found out he was possessed by a demon that lived in the basement.
Luckily, they were Catholic! They simply called up their priest who got on the horn with another priest that could practice an exorcism! Whew! That was a close one. If they were Methodist, they would have been screwed!
While it's easily explained that Catholics are more gullible than most, I'm not sure that could suffice as an explanation. When exorcisms "work" (do they? these "based on a true story" and "reenactment" stories are always exaggerated - what was the REAL outcome? Lasting effects, or just temporary? Kid starts demanding attention again? Kid goes off the deep end?), it's difficult to really figure out if the kid was just acting for attention or loony but scared enough to act straight again.
Bat shit crazy isn't something that can be cured - and kids randomly starting to act like they are literally bat shit crazy and possessed, while it does seem like a cry for attention, seems a bit extreme. Usually kids fail to hold up a perfect act, and good parents just beat the shit out of the kid after a certain point in time (little fuckers deserve it if they are truly acting like a demon for a few days/weeks).
Then again, the power of suggestion is strong during the exorcism routines. Maybe they are mild ADHD with a hint of bat shit crazy syndrome - perhaps a real and suggestive enough routine is enough for those that at least remotely believe in the concept of god, satan, angels, and demons.
The other explanation: demons do possess others, but maybe they have gotten clued in enough that possessing certain "types" of people is a worthless endeavor. Nothing says "fuck you angels and god!" like getting trapped in a person labeled crazy and sent to the psych ward to live the rest of their days.
Curious if there have been any truly bat-shit crazy, seemingly possessed people, who were sent to a mental institution only to end up recovering some time later... but of course nobody believes them, and leaves them locked up. :hmm: