Hypnagogic hallucinations and sleep paralysis

You wake up in bed but can’t move. You also hear, see and/or feel things. This is what hypnagogic hallucinations are about.

Hypnagogic hallucinations are vivid perceptual experiences that occur early in sleep. They consist of very experienced dreams that involve visual, tactile and auditory phenomena. Hypnopompic hallucinations, in contrast, are similar experiences that occur upon awakening.

The term pomp (act of sending) in reference to hypnopompic hallucinations was first used in 1918 by Myer to describe these phenomena during the transition between sleep and awakening.

The first description of hypnagogic hallucinations was made by the French psychiatrist Baillarger in 1846. This psychiatrist called them psychosensory hallucinations. The term hypno- (dream) and –agogos (induced) was introduced by Maury in 1848 to designate the hallucinations or illusions that announce sleep.

So, These hallucinations occur when the subject believes they are awake. The person can see, hear and feel, but cannot move. Therefore, hypnagogic hallucinations are closely related to sleep paralysis.

Prevalence and history of hypnagogic hallucinations

The prevalence of these hypnagogic and hypnopompic hallucinations in the general population they occurred in 25-30% of people affected by narcolepsy (2). In 1957, authors Yoss and Daly included these hallucinations in the diagnostic criteria for narcolepsy. These hallucinations have also been seen in disorders of excessive daytime sleepiness; They were frequently seen in patients with sleep paralysis before falling asleep. (3. 4)

Furthermore, some psychoactive substances, such as khat (5) and hashish (6)have been related to the induction of hypnagogic and hypnopompic hallucinations.

Read Also: Getting away from conflictive people improves health and soul

Sleep paralysis and hypnagogic hallucinations

Sleep paralysis is a generalized and temporary inability to move or speak.. It occurs mainly during the sleep-wake transition. Hypnagogic hallucinations occur in them.

Sleep paralysis and hypnagogic hallucinations were important features of the nightmare. Popular culture embellished these symptoms with supernatural interpretations. So, It was thought that sleep paralysis and hallucinations could be caused by visits from demons and spirits..

In 1834, the author Mcnish first defined the nightmare:

“The imagination cannot conceive the horrors to which it frequently gives rise…Everything horrible, loathsome, or frightening in the physical or moral world is presented before it in a fearful matrix; …In one moment you may have the consciousness that an evil demon is at your side; then, to avoid the sight of such a heinous object, he will close his eyes, but even so, being fearful makes its presence known; because his icy breath is felt spreading over his face, and he knows that he is face to face with a demon. Then, if he looks up, he beholds horrifying eyes glaring at him and an aspect of hell smiling at him with even more hellish malice. Or, he may have the idea of a monstrous witch crouching on his chest, motionless and evil.”

The quote above is a description of the nightmare written over a century ago. Reading this and other similar reports, it becomes clear that The term has undergone a change in meaning over the last 150 years or so. The term has more recently been used to denote highly experienced dreams, with unpleasant content, and that produce a significant sensation of fear in the subject, waking them up on many occasions.

Incubus: the nocturnal demon

in his book On the Nightmare, Jones explains that the word nightmare originally meant “fanatic of the night” or “nocturnal incubus.” These nocturnal demons became responsible for terrifying dream experiences.

Read Also: Repressed emotions are recorded in our body

An incubus is a demon that, according to popular European mythology of the Middle Ages, placed itself on sleeping women. Legend has it that the demon’s intention was to have sexual relations with the women on whom he perched. His objective, sometimes, could be to have offspring with the raped woman, as told in the legend of Merlin. (8) The female counterpart of him, which perches on the sleeping man, is called the succubus.

Incubi visited people at night and sat or lay on their chest, paralyzing them. Jones notes that this belief was almost universal across all ages and cultures. Thus, it seems that the hypnagogic hallucinations we speak of are considered, in a certain way, the cradle of the appearance of night demons.

These types of hallucinations, in addition to sleep paralysis, They are currently studied as symptoms within narcolepsy. However, it seems that these phenomena can also occur in healthy subjects. (9)