Verified by 
Jason struggled to open his eyes as the oppressive pressure on his chest became more severe. He sensed a presence in the room and felt her weight pushing down on him as he struggled to breathe. As his eyes opened slightly, he saw the shadowy figure above in the dimly lit bedroom. Her presence and a vague sense of dread filled him as he realized that he could not move. No matter how hard he willed his body to come to life and take protective action, nothing happened. What was happening and why? Time stretched on and his fear grew. Finally, his arms and legs responded and he sat up, finding himself alone in the room and shaken by this frightening visitation. He found it difficult to fall back to sleep and wondered what had happened. Had he somehow been violated? Off and on during the next day, he shuddered as he thought back on the unearthly presence he had encountered in his bedroom.
Jason's experience, surprisingly, is not that uncommon and is certainly not the most dramatic report of what is sometimes referred to as an incubus attack. In this case, it may be more appropriate to call it a succubus attack as that is the term used to denote the demonic female presence. This kind of experience is commonly reported around the world but with differing mythological explanations. For example, in Japan, they have been referred to as kanashibari, in China as ghost oppression, and in England and America as the Old Hag. Frightening and overwhelmingly realistic, these experiences are another example of a parasomnia, specifically, sleep paralysis. They can be hypnopompic (occurring while awakening) or hypnagogic (occurring while falling asleep) and are associated with frightening imagery or hallucinations.
The idea of the incubus attack is based in the medieval lore of the nocturnal demonic visitation. In one version of this lore, the demon is able to take on both male and female human shape and potentially impregnate a woman, causing her to give birth to a demonic child. The demon would initially take on the form of a female, known as a succubus, which would mate with an unsuspecting male victim. Capturing his "seed" the demon could then take on the male form, known as the incubus. The incubus would then mate with a female victim who could be impregnated with "demon seed." This frightening explanation for these nocturnal experiences is still embraced by some today, and many people who have had this experience find the demonic explanation convincing, at least initially, because the experience is so intense and apparently real.
Other explanations have, of course, been offered. For example, an embarrassing nocturnal emission might have resulted from an uninvited demonic visitor. An unexplained pregnancy may have been explained as the result of a visit by an incubus.
The scientific explanation for the incubus attack is that the person experiences a state dissociation in which part of the mental apparatus comes to conscious awareness even as the rest of the brain is in the REM stage of sleep. The body remains paralyzed so as to prevent acting out the dream. The realization that it is not possible to move contributes significantly to the unpleasant and frightening quality of this event. In addition, a potential sexual aspect to the experience is provided by the physiology of REM sleep which causes erection in men and lubrication in women. Awakening from a frightening experience and subconsciously recognizing an erotic bodily feeling lends itself to seeing a connection between the experience, and the working of dark and evil forces. The conscious experience is a combination of dream mentation superimposed on the sensory background of the room in which the person is sleeping. Long before Hollywood perfected the green screen technique or computer graphics allowed for the easy integration of the fantastic with the realistic, the brain was able to seamlessly blend together the inner world of the dream with the outer world of sense perception during these state dissociations.
It must be emphasized that for the person who has experienced an incubus or succubus attack, the rational, scientific explanation may lack the powerful emotional force of the demonic explanation. Even for trained scientists who have had these experiences, shaking the belief of having been visited by a malignant force is very difficult. An interesting account of this may found in Ronald Siegel's book, "Fire In the Brain." Many patients seeking reassurance will agree that the state dissociation explanation makes good sense but ...
The incubus attack is just one example of what can occur during state dissociations in sleep. There is also a great deal of sleep-related sexual mentation and potentially many sleep-related sexual behaviors. In future posts, these interesting and potentially disturbing experiences will be discussed.
