“Folie a deux” is “madness of two” where it was believed that two or more people share delusional beliefs and or hallucinations. This is not in the newest iteration of the DSM. The new iteration of the DSM does not distinguish “delusional disorder” from “shared delusional disorder” either. The new iteration of the DSM, the DSM V, takes into account the cultural environment of the person experiencing the phenomena. So if then, two or more people share the same delusional belief, it’s technically not a disorder if the shared belief is present in the person’s particular culture.

Tibetan Buddhists go on very long “prayer walks” where with stylized “shoes” on their hands they walk in a straight line. They place their hands together in front of their chakras; then lay flat on the ground, get up, walk a few steps, and repeat for many hundreds of miles. In Tibet, when someone sees this person on a prayer walk, they may say to themselves “There goes a very holy person on a very holy mission.”

Take this behaviour out of context and let’s say this person does a prayer walk in the middle of Lethbridge, Alberta. The police may be called and the person attempting the prayer walk may soon find themselves in the drunk tank or local psych ward. Taken out of the cultural context, their behaviour may not be viewed as holy or prayerful by any means.

Previous to modern science, when someone had a seizure or had taken ill, the immediate diagnosis was that they were possessed by the devil or devils. If the person was lucky, they would receive an exorcism. If not so lucky, as in during the Spanish Inquisition, they would be burned at the stake.

Possession is where an invading entity, not living or dead, hijacks the body of a person in order to wreak havoc in reality and hopefully propagate itself by possessing more people. Post modern science, we now know that often disease has a much more physical explanation. Take a viral infection for example. A viral infection happens when a virus, a non living or dead entity, invades a cell. The virus hijacks the cell in order to propagate itself in the host.

See what I did there?

Whether or not a person believes in invasive entities as the root cause of the phenomena of possession is irrelevant. With or without your personal belief of “the spirit,” many people, cross culturally and world wide, experience the phenomena. The Catholic Church has a “Rite of Exorcism” in the Rituale Romanum, along with Rite of Marriage and Last Rites of Death. The Vatican takes the phenomena so seriously that there is an exorcist training course available to priests. Exorcism as a cure is ingrained within Catholic ideology and has been since the beginning. St. Michael the Archangel can probably be attributed as the first exorcist, as he, according to John Milton in “Paradise Lost” cast Lucifer out of heaven in a great battle, that in a lightning flash created hell and the devil all at once.

The differentiation between what is religious belief and shared delusion is a fuzzy line indeed. Reality is not entirely made up of atomistic facts, and neither are atoms atomistic themselves. We have increasing ability to theorize and search for smaller and smaller bits of reality to only find we need to search smaller and smaller still. Eventually, a wall of thought is hit. Perhaps the underlying structure of reality are “strings” at various vibrational frequencies. Perhaps we exist in a holographic projection. Whatever hierarchical and linear conclusions can be made within the worldview, there still exist non-binary, non point by point reductionist concepts and phenomena, that science and philosophy must “silently pass over” as Wittgenstein says.

It’s probably not the devil that is possessing people world wide. However, the people being possessed think it is. If they experience a cure to the symptoms by undergoing exorcism, one must ask why is that method less valid if indeed the afflicted find their resolution?
However, given the almost unquestioned legitimacy given to the DSM (especially among students), and almost universally unquestioned legitimacy given to the “chemical imbalance of the brain hypothesis” one must also ask, are we really doing anything any different than reinforcing the prevailing “scientific” consensus until knowledge of the facts change? Should technology progress far enough to disable what we contemporarily consider to be factual, would our present knowledge be considered as valid as a diagnosis of “hysteria” was in the 1930’s?

Eric Idle says “The fact’s don’t change, it’s our knowledge of the facts that do.”

In opposition, Albert Einstein says “If the facts don’t fit the theory, change the facts.”

What do you say?

For information on “delusional disorder” see the DSM-V, available for reference at the U of L library.

If you need an exorcist, god help you.


2 thoughts on “What used to be “Shared Delusions”

  1. I really enjoyed reading this blog post! I like how you described how certain beliefs or delusions are only considered delusions depending on what context you find them in.
    The idea of delusional disorders really interested me, so I looked at a study which discusses why some people form these disorders. The article noted that there are two main theories as to how delusional disorders form and are prolonged: 1) Delusions are formed to alleviate a fragile sense of self, so that the person can externalize negative events onto others, and 2) Delusions are a result of a cognitive or perceptual deficit that doesn’t allow people to properly evaluate their beliefs in a rational and practical manner (Abdel-Hamid & Brune, 2008, p.229). I’m just curious if you’d be able to relate these theories to your discussion of delusions and cultural context at all?

    Abdel-Hamid, Mona & Brune, Martin. (2008). Neuropsychological Aspects of Delusional Disorder. Current Psychiatry Reports, 10(3), 229-234. DOI: 10.1007/s11920-008-0038-x


  2. Intelligent read! While it touches on social cognition I think the broader issue is one to do with philosophy, which you briefly discussed. Basically, if I understand correctly, true knowledge is impossible, we are inherently limited to a small and imperfect window provided by chemical reactions in the brain with which to see the world.

    How we define a delusion seems to be when that window doesn’t see what the majority of other people see. But who knows, maybe that is the correct window into the world and the rest of them are warped. The truth is we are epistemologically limited, there is actually a term for it called “the egocentric predicament.” The issue was of such grave importance to Charles Sanders Pierce that he actually drew a line between the impossible-to-grasp “real world,” and everything that occurs within your own mind, which he dubbed “The Phaneron.”

    Now assuming we know nothing is a bit of a useless view to take when trying to operate in the real world. If a bear is marching at you, its best not to question weather or not its a shared delusion and just run. Therefore, while we can acknowledge (as you do in the closing note) that we can’t really know if people are truly having delusions, or if perhaps we’re just operating in a reality that we will only come to realize was misguided later on, its best to just keep trying our best at performing good science. Life is a bit more fun when you feel like you’ve learned something, afteral.


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