Hypnagogic Hallucinations

These are visual, auditory, and/or sensory experiences that occur to a person while going to sleep, often during sleep paralysis. Many cultures have written about these experiences as a sort of spiritual gateway into another world, such as being attacked or preyed upon by bad spirits, though modern science reduces them to mere hallucinations.

They are associated with sleeping disorders like narcolepsy and mental health disorders, or those who take some types of antidepressant medications, although people with normal sleep and mental health can also experience them. Modern science is still unsure about the causes of these visions, although they seem to be neurologically similar to daytime hallucinations and dreams.

Interestingly, despite cultural differences, many people tend to see strikingly similar types of figures during these episodes. Often they are horrific, traumatic, and threatening. A very common figure seen during these episodes is called a “shadow person”. Many people see one or two shadow people with a hat on, sometimes moving, sometimes standing still or hovering above oneself.

Sometimes these figures will seem to exert pressure on a person undergoing the experiences, often on their chest, neck, or groin area. In the middle ages these spirits were called “mares” or “nightmares” and they are the origin of the modern term we use for bad dreams.