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.
