The Nightmare and the Hag
The incubus that sits on the chest, and sleep paralysis.
In the Texts
The incubus of the manuals comes by night, presses on the sleeper’s chest so that he cannot breathe or move, and is seen or felt as a body; the folk called it the hag, the mare, the pesanta, and hung the holed stone and the knife against it. Canale lists the remedies that cool and dry the body against it, and the amulets.
What Medicine Makes of It
Sleep paralysis is the intrusion of the muscle atonia of dreaming sleep into waking: the sleeper wakes, cannot move, feels a weight on the chest from the shallow breathing of REM, and often sees or senses a presence, which the dreaming brain supplies. About eight per cent of people have it at some time, more among students and the shift-working. David Hufford, in The Terror That Comes in the Night (1982), showed that the Newfoundland “old hag” was described identically by people who had never heard the tradition, and argued that the experience makes the belief, not the belief the experience. J. Allan Cheyne’s surveys since 1999 have mapped the three clusters: the intruder, the incubus pressing, and the vestibular sensations of floating and flying.
The Evidence
- Sharpless and Barber’s meta-analysis of 35 studies (2011) put the lifetime prevalence of sleep paralysis at 7.6 per cent in the general population, 28 per cent in students, and 32 per cent in psychiatric patients.
- Cheyne, Rueffer, and Newby-Clark (1999) analysed 2,000 episodes and found three factors: the intruder (a sensed presence, fear), the incubus (pressure on the chest, difficulty breathing), and the vestibular-motor (floating, flying, out-of-body), which map onto the demon, the hag, and the witch’s flight.
- Jalal and Ramachandran (2014) proposed that the sensed presence arises when the paralysed body’s map in the parietal lobe is projected outward, a “shadow” of the self; the hallucinated figure is the dreamer.
- Sleep paralysis is more frequent with sleeping on the back, with irregular sleep, and with anxiety and PTSD; a Cambodian refugee study (Hinton et al., 2005) found 42 per cent had it, and that fear of the spirit made it recur.
- The Newfoundland “Old Hag” survey (Hufford, 1982) found 23 per cent of 93 students had experienced it, and that those who had never heard the tradition described it in the same terms as those who had.
Where They Part
Here the texts and the clinic describe one thing in two languages, and the folk remedies (lying on the side, keeping regular hours, the avoidance of heavy suppers) are the modern advice. The hag stone over the bed changes nothing in the physiology; what it changes is the dread, and dread is what brings the episodes back.
In the Materia Medica
Sources
- Hufford, D. J. (1982). The Terror That Comes in the Night. University of Pennsylvania Press.
- Cheyne, J. A., Rueffer, S. D., and Newby-Clark, I. R. (1999). “Hypnagogic and hypnopompic hallucinations during sleep paralysis.” Consciousness and Cognition 8.
- Sharpless, B. A., and Barber, J. P. (2011). “Lifetime prevalence rates of sleep paralysis.” Sleep Medicine Reviews 15.
Historical and interpretive; not medical advice.