Belief in the possibility of demonic possession has waned since the advent of sophisticated medical knowledge. What had previously been considered to be examples of control of an individual by a spirit or devil are now commonly accepted as numerous forms of mental illness, easily explained by nervous system activity. If all types of behavior (including emotional states and cognitive states) are produced and mediated solely by the brain, there leaves no potential for such a phenomenon as demonic possession to exist and such cases would clearly be instances of various illnesses. However, neuroscience has not yet been able to explain all of the characteristics common to purported cases of demonic possession (1).
A possessed individual is typically characterized by having strange physical ailments or disfigurements; verbal outbursts, mostly obscene or sacrilegious in nature; violent behavior and vulgar behavior; bodily spasms and contortions; ability to speak languages never before studied; self-mutilation; "superhuman" abilities such as psychic abilities, abnormal strength, or an ability to perform behaviors out of the realm of human possibility such as levitation; cessation of normal bodily functions for periods of time, including breathing and heart beat; and a pronounced revulsion to symbols, places, people, objects, and ceremonies having any religious context. Other phenomena associated with the presence of a demon include an acrid stench; marked decrease in the temperature of the room which a possessed individual occupies; writing appearing out of nowhere; sounds and voices arising from nowhere; and objects moving on their own and destruction of objects in the room, without anyone having laid a hand upon them (2), (3).
Despite the striking quality of this description, the expansion of the fields of medicine and psychology has led to diagnoses other than demonic possession for individuals who present circumstances similar to those mentioned above. These sorts of cases are now readily explained in terms of abnormal functioning in the brain and nervous system. There are various disorders which may mimic demonic possession; these include schizophrenia (and other periods of psychosis), dissociative identity disorder, and Tourette syndrome (4).
Schizophrenia is characterized by the presence of delusions, hallucinations, disorganized speech, disorganized or catatonic behavior, affective flattening or inappropriate emotional responses, avolition, and alogia. General psychotic episodes, such as might accompany mood disorders, can also closely simulate a state of demonic possession by hallucinations or delusions. The delusions can be ones of thought insertion, thought broadcasting, delusions of guilt, delusions of grandeur, such as being God (or a demon), or delusions that God (or a demon) is speaking to the person and giving commands for a special mission (5).
The resemblance between several of these criteria and demonic possession is rather striking. The inappropriate emotional displays seen in psychoses correspond to those frequently documented in cases of demonic possession where the possessed individual expresses either flattened affect or outbursts of extreme affects; a possessed individual will often laugh at situations which are morbid, such as injury to another individual, or crying and screaming when there appears to be no appropriate stimulus for such a response, such as being presented with a crucifix or holy water (6).
Psychosis is generally thought of as a break with reality; society will frequently consider individuals who believe themselves to be possessed as delusional and not "in touch with reality." An individual who appears to be possessed and claims to be a demon may be viewed as suffering from a delusion of grandeur. Family members and friends caring for possessed individuals can become extremely disturbed by the state in which the individuals present themselves and often request an exorcism as a last resort. One might think of this as an example of Folie à Deux, in which one individual develops a delusion while in a close relationship with another person who already has an established delusion; the delusion is of the same content for each individual (5). It is possible that the possessed individual initially suffers from a delusion and eventually convinces loved ones that the possession is real.
The paranoid thinking present in many instances of psychosis is similar to that of an individual who is possessed and fears all items, people, and situations that contain religious themes. An individual who is possessed will react violently to the presentation of anything with a religious context, out of fear that harm will come to them; the reaction is elicited merely from being exposed to something such as a Bible or a priest. The disorganized thinking and speech that often occurs during periods of psychosis may also resemble the seemingly nonsensical speech a possessed individual may show (6).
Individuals who suffer from schizophrenia predominantly marked by catatonic behavior often arrange their bodies in bizarre or inappropriate postures for long periods of time; they frequently engage in stereotypic motor activity or have very prominent mannerisms and facial expressions. Conversely, these individuals might refrain from any movement whatsoever for prolonged periods of time, as if in a trance. This might be similar to the bodily contortions and exaggerated expressions of emotion noted in cases of demonic possession, as well as to the hypnotic-like state observed in possessed individuals (1).
The superhuman strength often exhibited by individuals who are possessed might be explained by the presence of a bipolar disorder; bipolar disorders are frequently accompanied by psychosis, particularly during the manic episodes. Manic individuals exhibit abundant amounts of energy and often have abnormal strength, similar to what can be seen in an individual who is possessed.
Schizophrenia, or any form of psychosis, is currently thought to be the result of a malfunctioning dopaminergic system, either a system which is too active or a system which is too sensitive. The dopamine system has been implicated in movement and coordination, emotional response, and the ability to experience pleasure and pain (7). It would then seem quite likely that many purported cases of demonic possession are merely instances of dopamine systems failing to work properly, given the aforementioned abnormal motor and affect behavior. It also seems quite plausible that individuals who believe themselves to be possessed are in a state of severe ahedonia.
Another disorder which has frequently been misdiagnosed as demonic possession is dissociative identity disorder, formerly known as multiple personality disorder. The criteria for this disorder is the presence of two or more distinct identities or personality states, each with its own way of perceiving, relating to, and thinking about the environment and the self; at least two of these personalities or identities recurrently take control of the individual's behavior; and an inability to recall important personal information that is too extensive to be dismissed as ordinary forgetfulness (8). The separate identities involved in this disorder and the physical changes that denote dissociation could certainly reflect the abrupt change in personality manifested by those who appear to be victims of demonic possession (9).
A demon in someone who is possessed has its own purpose, own beliefs, morals, and attitudes, mannerisms, even its own style of speech, including a different voice. Each of these is distinct from those of the individual prior to possession and to an observer, it is clear that a change has occurred in the individual. In addition, an individual who suffers from demonic possession may not be able to recall the periods of time in which the demon manifests itself, resulting in blackouts and time loss (6). This is quite comparable to the manifestation of multiple personalities, each unique from the other, in an individual with dissociative identity disorder. The different personalities also have different motivations, ways of behaving, types of knowledge, and types of speech. The differing speech patterns between identities might partially explain the phenomenon of "speaking in tongues" often witnessed in victims of demonic possession. Time loss and blackouts are also extremely common to individuals with dissociative identity disorder; the unrecalled periods of time occur when another personality is in control (10).
Extreme suggestibility and hypnotizability are prevalent among individuals with dissociative identity disorder, which may be important if someone has suggested to an individual with the disorder that they are not mentally ill, but are in fact possessed by a demon. An individual with dissociative identity disorder who has had this suggested to them might come to believe they are inhabited by a demon (11).
Motor activities common to those with dissociative identity disorder include anesthesia, eye rolling (especially during switching to another personality), and pseudoseizures (11). These are behaviors that are commonly observed in individuals who are reported to be possessed by a demon; individuals who are possessed may be unable to feel pain in certain areas of their body and some of the distortions involved in possession include eyes rolling back and seizures (6).
The commonly accepted etiology of dissociative identity disorder is an early history of repeated trauma and abuse, often to horrific degrees (12). There is currently no biological theory concerning the origin of dissociative identity disorder; this creates both a direction for future investigations into the disorder and a possibility that demonic possession is an occurrence that cannot be explained in terms of the brain.
Another disorder that has probably been mistaken for demonic possession throughout time is Tourette syndrome, characterized by multiple motor and vocal tics (13). Motor tics can range in complexity from eye blinking to sticking out the tongue to rapid jerking of the body and writhing. The vocal tics can be sounds such as coughing, barking, growling or repeating words and phrases over and over again. Perhaps the most well-known symptom of Tourette syndrome is coprolalia, the screaming of obscene and foul language (14).
It is obvious how these behaviors can be misinterpreted as demonic possession; possessed individuals are often described as flailing and thrashing about and shouting obscenities, sexually aggressive phrases, violent threats, and sacrilegious statements.
There is also a high rate of comorbidity with obsessive-compulsive disorder in individuals who have Tourette syndrome (14). It seems likely that there would be a high frequency rate of obsessions with religion in individuals who claim to be possessed by a demon.
The origins of Tourette syndrome are thought to lie in either the dopaminergic system or the noradrenergic system. It is believed that the disorder results from either supersensitivity in the dopamine receptors or hyperactivity in the functioning of the norepinephrine system (14).
The concordance of the putative biological causes of schizophrenia and Tourette syndrome seem to imply some type of connection between the two disorders, and the phenomenon which they both imitate, i.e., demonic possession. It also lends credence to the belief that the brain is responsible for types of behavior which may initially seem remarkably beyond the realm of normal human behavior.
However, there is quite a bit about supposed demonic possession which cannot yet be explained by biology. This category includes such phenomenon as levitation, wounds appearing upon the victim that have not been inflicted by the self or another concrete source, knowledge of languages never before studied, sometimes never even heard, and psychic abilities such as knowing facts about other individuals that have never been met. In addition, the accompanying situations related to the area around possessed individuals do not seem to be explainable in terms of the brain or any aspect of biology; science cannot yet explain the distinct decrease in temperature of the room the individual occupies, the appearance of writing and sounds from an unseen force, and the movement of objects on their own (2).
One can come to two conclusions when faced with this evidence. The first is that the cause of such circumstances will eventually be determined by further study of the brains of reportedly possessed individuals. This might reveal that there is something biologically (and entirely secularly) unique about such individuals which allows them to be capable of creating such phenomena by themselves; in this case it could be determined that demonic possession is nothing but a myth perpetuated for centuries. On the other hand, the possibility that demonic possession is a real occurrence cannot yet be rejected; no thoroughly decisive evidence exists to the contrary. What is currently known about science cannot fully explain every situation reported to be a case of demonic possession, at least not by the methods which science currently employs. Until science can explain each detail, if indeed it ever can, one cannot dismiss the possibility that demonic possession is a real and true phenomenon.
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11) Cast Out What?