Conversion disorder.

Also group psychosis.

However this won't help your argument if they choose to believe their woo.

In the Christian tradition, to cast out a devil (or demon) was a demonstration of one's divine credentials. The demons, or lesser devils, were always known to be Satan's servants, and, according to tradition, may be angels who joined Lucifer in his unsuccessful heavenly coup attempt. All of this makes for a wonderful fairy tale, but we must also keep in mind that without the Devil, there is no Christianity. The Devil is the keystone in the arch, without whom the Christian faith crumbles. Remove from the Bible the story of Eve's encounter with the Serpent and Adam's fall (or original sin), and there is no reason or purpose for the plan of salvation or the New Testament story. No Satan, no Christ.

Take away the miracles and Jesus just becomes your provertal 'good man'. So for Xians the miracles they must have.

Growing up in Haiti, with most people involved in voodoo, I definitely saw "demons" or whatever it was; people suddenly going berserk, where some little girl would sling three adult men across the room, sometimes we'd hear something banging inside a closet, footsteps running up and down the hall, the sound of rocks hitting the roof, animals falling dead suddenly the moment someone "cast a demon" out of someone, things floating in the air, articles disappearing and reappearing later in very weird places, something waking both me and my friends up in the night, choking us, etc.

Whenever these things occurred, we'd use the "name of Jesus" to command them to go, or to stop the manifestation, and it instantly would. Later, when some of these things started to occur in the US, I'd had enough..I simply told any bad stuff to stop happening, and it would..no religion involved.

I also noticed that these bad things mostly happened with people who believed in them; I.e., I seldom saw them happen with atheists, except for once in 1968, at Union School, the Port-au-Prince, Haiti, diplomat children's school, and there were several people present who believed in spirits, so could have been the ones subconsciously manifesting the weird happenings.

Since we are matter, which is energy, and we are involved creating our own realities, I suppose we are the ones doing it, except that alleged secret government whistle blowers like Simon Parkes say that "demons" are energy beings that exist simultaneously in both our 3rd dimension, and the 4rth dimension, which is why they can sometimes be seen, even photographed, but usually seem to turn into smoke and vanish.

He, and others like him, say that these beings occupied earth first and resent humans taking over their planet, so keep making bargains with humans to give them powers to hurt others through spells.
Dunno.
I listen, read,, consider them, wonder if there is some truth in all the theories.
One thing I observed is that people who mess with the "demons" often go insane, including several friends of mine who were just "having fun" messing with spells. Of course, I don't know if they were insane to begin with, which is why they did it.

I kind of think there are demons but not as entities that exist beyond our minds. Many people have demons, arising from trauma, life experiences, life choices gone bad. When those things overwhelm the good in us, psychopathology can "possess" us. Descriptions of demon possession often have a lot in common with symptoms of severe mental illness. Hundreds of years ago, schizophrenia, psychopathy or paranoid delusions probably could not be understood by people as anything but "possession" by some demonic spirit.

I don't believe in god, angels, heaven, hell, Satan, or miracles, but my demons are real.

And that surprises you?

Most christian religions have exorcists to cast out demons.They thrive on lots of supernatural critters - angels, demons, archangels, devils and a supersupernatural god that is more supernatural than the other supernaturals.

Of course they believe in demons.