Hypnagogia

Hypnagogia (also spelled hypnogogia) and hypnopompia are experiences a person can go through when falling asleep in the case of hypnagogia, or waking up, in the case of hypnopompia. When in a hypnagogic or hypnopompic state a person can have lifelike auditory, visual, or tactile hallucinations (collectively known as hypnagogic hallucinations), perhaps even accompanied by full body paralysis. The individual is aware that these are hallucinations; the frightening part, in many cases, is the inability to react to them, even being unable to make a sound. In other cases one may enjoy truly vivid imaginations. The term was coined by the 19th century French psychologist Alfred Maury. Many artists, musicians, architects, engineers, and others demanding creativity to be successful have benefited from the hypnagogic state, where the mind can be totally free and open to creative and new ideas.

Hypnagogia differs from hypnosis in that under ordinary hypnosis, people are physically inactive, and generally find their mental stimulus to be absorbing to the point that they don't differentiate between that stimulus and reality. In hypnagogic states, a person may appear to be fully awake, but still has brain waves indicating that they are still technically sleeping. Also, in hypnagogic trance states the individual may be completely aware that they are sleeping or hallucinating, while this is not generally the case with hypnosis.

It is not an uncommon occurrence with 30 to 40 percent of people experiencing it at least once in their lives. However, it can be a sign of other problems such as narcolepsy or temporal lobe epilepsy.

People in the hypnagogic state sometimes experience sleep paralysis, a condition in which the body is temporarily paralyzed after waking or before falling asleep. This is thought to happen when a person enters or leaves REM (rapid eye movement) sleep too quickly. During REM sleep the brain blocks the signals that allow the limbs to move to ensure that we do not act out our dreams. However, when experiencing hypnagogia or hypnopompia, the individual is still conscious of their surroundings, effectively dreaming while still awake. This fact enables lucid dreamers to enter the dream consciously directly from waking state (see wake-induced lucid dream technique).

The cause of hypnagogia and hypnopompia is usually associated with the varied sleep disorders, primarily insomnia.

Hypnagogia is often proposed as an explanation for phenomena such as alien abduction and visions of saints or demons, the Virgin Mary, and Jesus Christ.