Psychotics have been in control for *millennia" not only centuries!
Check out www.regena.com/psychopaths.htm
THE PSYCHOPATHIC TENDENCY IN WORLD POLITICS
By Jerry Russell and Richard Stanley www.regena.com/psychopaths.htm

Heres an excerpt:
For many years, psychologists have studied the frightening reality of psychopathic or sociopathic personalities -- the serial killers, the child abusers, the pathologically consistent liars and incorrigible thieves. The scientific study of these individuals was systemically organized by Hervey Cleckley and his 1941 classic "The Mask of Sanity", and today the specialist Robert Hare www.hare.org is one of the foremost authorities in the field.
According to Hare, the key emotional and interpersonal traits defining the psychopathic personality syndrome are: a smooth, glib capability to lie, manipulate and dissemble; a completely callous lack of empathy or concern for others; shallow emotional affect and lack of remorse; and egocentric grandiosity. While most psychological studies of psychopathy have been based on prison populations, there's an emerging (and controversial) recognition that many individuals with this cluster of personality characteristics, are not in prison. "

Psychopaths have no conscience and can feel no empathy so there is no limit to their depravity (concentraton and rape camps, wars that they start, experimenting on humans and animals etc.

I think the belief in demons, aliens etc comes from the practice of psychopaths acting like us to blend in and not get caught. For instance, their fake concern at military funerals. Like tapeworms, these parasites are hard to detect.