Hypnagogic hallucination: Hallucinations experienced when falling asleep

Hypnogogia is the transition moment from being awake to sleep. It occurs due to the fact that parts of the brain don’t fall asleep at the same time. It’s been shown that the first to fall asleep are the frontal part of the brain and the last ones are posterior parts. While the brain is falling asleep it is possible to experience hypnagogic hallucination. The most typical hypnagogic hallucinations are visual and auditory. The visual ones typically involve geometric figures or patterns, whereas auditory hallucinations can be beeping noises, high-pitched noises or even more unclear noises. However in severe cases of anxiety auditory hallucinations may become more specific, as they can even take the form of voices, which typically represent rapid thought of an individual. One of the common mixtures of both types of hallucinations is an exploding head syndrome. It involves a hallucination of loud band-like noise accompanied with a flash of bright light, resembling an explosion. 

Those hallucinations can be very scary, as much so that they can cause an individual to wake up and even jump out of bed. This happens when the frontal lobe, which is the reasoning center in the brain, is not able to reason about the images or sound we experience as it is already asleep. Those hallucinations don’t have any direct negative effect, maybe accept losing sleep. However they can be dangerous as an individual is not very conscious of what he is doing and by accident he can harm himself.

The exact causes for those hallucinations are unknown, however factors that have been observed to be associated are insomnia, tiredness, alcohol or drug use, anxiety, stress, narcolepsy, mood disorders, such as depression or bipolar disorder or epilepsy.

Most of the time there is no need to worry as those hallucinations can be natural in a healthy person. However they may cause anxiety and constantly interump individual’s sleep.

Cirino, E. (2021, October 13). Hypnagogic Hallucination. Healthline. https://www.healthline.com/health/sleep-health/hypnagogic-hallucinations.

SciShow. (2017). Why We Hallucinate While Falling Asleep. [Video]. YouTube. https://www.youtube.com/watch?v=1RvBvYrklXM.