Hypnagogic hallucinations

How it works

Hypnagogic means “leading into sleep”. Hypnopompic means “leading out of sleep”¹². During the shift between waking and sleep, different parts of the brain change state at different times. The parts that make dreams can be active while the parts that handle waking perception are still switched on¹. Dream content gets mixed in with real sight and sound.

The common experiences are geometric patterns, faces, landscapes, and scenes; hearing your name, a doorbell, a voice, or a snatch of music; a feeling of falling or floating; and a touch or a hand on the body¹. After hours of a repeated task such as a video game, you may see it replay as you fall asleep. This is called the Tetris effect³.

Between 25% and 37% of people report these hallucinations¹. They are more common in teenagers and young adults, after lost sleep, with an irregular schedule, and under stress¹. They often go together with sleep paralysis.

Is it a problem?

No. They are not a sign of mental illness. Hearing your name once at the edge of sleep is a normal brain doing a normal thing. They need no treatment.

See a doctor if hallucinations happen while you are fully awake during the day, or if they come with sudden weakness when you laugh or with attacks of sleep you cannot resist. That pattern can be narcolepsy, which is treatable⁴. Also mention them to a doctor if they start after a new medicine.

History and culture

The painter Salvador Dalí used the state on purpose. He napped in a chair holding a key over a plate. When he fell asleep the key dropped, the noise woke him, and he painted what he had seen¹. The inventor Thomas Edison used the same trick with steel balls¹.