The randomness has a name: Hypnagogic hallucinations

You lie in bed, waiting for sleep to come. Your thoughts spin around everything that has happened in the day, and everything you will have to do the next day. As your body gets more and more relax, it gets harder and harder to follow the train of thoughts. The mind jumps randomly around, and strange ideas insert themselves into your mind. You find yourself looking at something, and it takes a moment to realise that it isn't real. Random lines flash past you in your thoughts. You are walking, and suddenly, you slip through the ground. Your body jerks, and you are startled awake.

This is called hypnagogic hallucinations, hypnagogic images or sleep images.

Hypnagogic hallucinations are normal

Phosphenes, as they usually look to me

Most of us experience this phenomenon regularly. It is extremely common to hallucinate while falling asleep. These hallucinations are a normal part of the process of falling asleep, and not in any way connected to mental illness.

The first and simplest kind of hallucinations is called phosphenes. When there is no visual input from the eyes, background noise from the nervous system will become visible as shapeless blobs of light. For me, they are usually blue or green. Staring at the darkness for a few moments is usually enough to induce the hallucination, and the longer I focus on it, the stronger it becomes.

This isn't necessarily a sign of falling asleep. Phosphenes can have other causes, such as pressure (for example from rubbing your eyes) sleep deprivation, or fever.

Visual hallucinations are common while falling asleep. After intense activity, especially after learning a new skill such as a computer game, visual hallucinations can be very detailed copies of the activity. This is called the Tetris effect. Other common themes are text or headlines, shifting patterns, landscapes and work scenes. Maybe my most common visual scene is the workbench in the flower shop where I work. It is welcome, because it simply means that I'm falling asleep. For a person with periodic insomnia, this is a relief.

All senses can be affected

The hallucinations aren't necessarily visual. It is just as normal to experience sounds and physical sensations. I have been lucky enough to hear music several times. The music can be a well known song, or it can be completely new. Some people hear their own thoughts spoken by their own voice. Footsteps, the doorbell, or a phone ringing are commonly reported sounds. Some people may experience an extremely loud noise. This is known as exploding head syndrome. It is rare, and harmless.

It can feel like the body is being stretched, compressed, lifted up or vibrating. I sometimes feel like my hands are floating in thin air. Some people have even reported smells or tastes. I know that I have hallucinated the smell of smoke at least once.

The hypnic jerk

A specific kind of hallucination can actually be so disturbing that we wake up. It's a startle reaction called the hypnic jerk. It feels like a "jump", and is usually accompanied by hallucinations of falling or slipping. For me, it usually feels like I fall "through the ground". This is apparently more common in stressful periods. Sometimes, after sleep deprivation, this is how we can notice that we are actually falling asleep in the day.

Hypnagogic hallucinations and lucid dreaming

Many of my lucid dreams start with this

For people who practice the WILD form of lucid dreaming, the hallucinations are valuable. They are a good sign that the body is actually falling asleep. The hallucinations can transform seamlessly into a dream. The trick is to stay focused on the images, while still allowing sleep to happen. This will usually take some practice.

For me, the best hallucination to get a WILD from is an image of a road or path. It feels easy to concentrate on. I imagine moving along the path, and at a certain point, the illusion shifts from 2D to 3D. When I stand on the road, the lucid dream has started.


For learning more about lucid dreaming, I strongly recommend paying a visit to LD4all. I have learned so much from the people there.

Sleep Paralysis: annoying, maybe frightening, but harmless

You wake up in bed, only to find out that you can't move. Not a single body part obey you, apart from your eyes. Your mind is partially clouded. Are you dreaming, have you been drugged, is something horribly wrong with your body? Something at the edge of your vision catches your attention. A tall, dark shadow stands between you and the window, slowly moving closer to your bed, not making a sound. You can't take your eyes off this threatening vision, and you try to scream, but no sound comes out...

Shadow hallucination. Bedroom photo by Aphoticbeauty

What is sleep paralysis?

If this sounds familiar to you, you have experienced sleep paralysis. The experience is most common immediately after waking up, and usually lasts for a few seconds. Because of the fear that can accompany sleep paralysis, those seconds can feel horribly long.

To understand what sleep paralysis is, we need to know a couple of things about sleep. Sleep is divided into several different phases: NREM 1, 2, 3, and REM. Every time we sleep, we cycle through those phases roughly once every 90 minutes. REM sleep is the phase where we usually dream. In this stage, the body (except the eyes) is completely paralysed. This is called REM atonia. If this paralysis didn't occur, we would have acted out all our dream, and potentially injured ourselves. When we wake up quickly, and directly from REM sleep, consciousness may return before we regain control over our muscles. This causes conscious sleep paralysis.

Hallucinations in sleep paralysis

It is common to hallucinate in this state. The scientific word for hallucinations upon waking up is hypnopompic hallucinations. Several theories try to explain where these hallucinations come from; some say that they are a result of natural brain processes during sleep which imitate stress and fear reactions, and some say that they are simply background noise from the brain. A common hallucination is seeing, hearing or otherwise sensing an intruder in the bedroom. As soon as we wake fully, the hallucination dissolves. Seeing a dark, humanoid shadow is an especially common hallucination. I used to experience this often in my youth. Now, I usually hallucinate footsteps, the doorbell, or a cat curled up on my bed.

Simply knowing that this is a hallucination helps against the fear. It is good to know that this isn't real, it is harmless, and will go away at least a few moments after muscles start working again. Most people experience this at some point. Some people experience it as much as once a week, and that can be a sign of an underlying sleep or anxiety disorder.

How do I get rid of it?

It is common to experience sleep paralysis more often if we are stressed or anxious. I have also heard stories of this happening after overuse of alcohol, tobacco, caffeine, or other psychoactive substances. Keeping a healthy sleep schedule and otherwise treating the body well may help prevent it.

Apart from the eyes and face, the first body parts to regain control are often the fingers and toes. It can be effective to focus on them. When control comes back in a finger, the rest of the body should follow within moments. I have often made the mistake of focusing on my voice first, and that has just added more stress.

If the hallucinations aren't too distracting, simply going back to sleep is also an option.

Many lucid dreams start like this

Sleep paralysis and lucid dreaming 

It is possible to experience paralysis both while falling asleep and while waking up, even if the latter is far more common. For people who are familiar with the WILD (Wake Induced Lucid Dream) technique, sleep paralysis can be used as an easy way into a lucid dream. The brain is already close to REM sleep. Some people have described how they simply roll out of bed, stand up, and find themselves in a fully formed lucid dream. It is probably a good idea to at least make it a habit to do a reality check after every sleep paralysis experience.

Further reading

LD4all's SP FAQ

Wikipedia article


First published April 2015, updated March 2026

Why do thoughts flow so freely in the shower?

This thought came to me, of course, in the shower. I was happily showering, with the lights off as usual (because that improves the state of creativity even more), and the question popped into my head.

It is well known that thoughts and ideas come easier into the mind in the shower or bath. It wouldn't surprise me if important inventions have been first thought of there. There is even a subreddit dedicated to shower thoughts. Browsing through it is entertaining, but it doesn't solve the question.

I have a theory that it is related to sensory deprivation. Basically, when the brain stops receiving clear signals from one sense, it compensates by cranking up the signal from other senses. This is why blind people often  have unusually good hearing, for example.

When there aren't any clear signals from *any* sense, for example in a sensory deprivation tank or simply half asleep in bed, the "background noise" of the mind gets cranked up. This is why we can hallucinate coloured blobs and static noise while we lie down in a dark room. A shower blocks the senses of hearing and touch effectively, by overloading them with noise signals. Turn the light off, and the sense of vision gets deprived too.

Some people have said that they have experienced actual hallucinations while showering with the light off. I haven't experienced that yet, but I certainly get more creative. Not only weird questions pop into my head, ideas for art and music frequently do.