The Sleep Disorders That Haunt Horror Films

In honor of Halloween, we explore the spookier side of sleep.

In Mike Flanagan’s Netflix series The Haunting Of Hill House, the haunting happens both figuratively and literally. The show creates and delivers highly affecting chills through a combination of literal ghosts, later-in-life hallucinations and the long-term effects of paranormal encounters. One character in particular, Nell, is especially troubled – not only by an experience with a ghost but with the sleep paralysis that has followed her ever since.

Hill House isn’t the only scary movie in which a sleep disorder looms large in the plot, by either exacerbating an already creepy situation or creating it. We dug deeper to look into why and how sleep and sleep disorders like sleep paralysis often play a major role in our favorite scary films.

Sometimes Fact Is Scarier Than Fiction

Perhaps, in part, the intersection of sleep and horror is accidental—scary things happen when it’s dark and that’s also when we sleep. But until recently sleep wasn’t super well understood and there’s still so much we don’t know about it. The act of sleeping can be unnerving because it puts us in a vulnerable position.

In 1951, sleep was explored as an enigmatic state in which bodies were at risk of being taken over by aliens in the film Invasion Of The Body Snatchers. While Invasion served as a metaphor for the fear and risk of the US being taken over by Communists, it also highlights a more basic fear that remains at the center of many of our scariest stories: the fear of losing control of our bodies and brains—something that almost always happens when we shut our eyes at night and drift off to sleep.

While the experience of sleeping is strange since it can cause feelings, thoughts and behaviors that are largely outside of the sleeper’s control—the effects of disordered sleep can range from odd or frustrating to downright disturbing. Below are a few fairly horrific types of sleep disorders and how they figure into the spooky:

Sleep Paralaysis

Probably the biggest inspiration for horror movies, sleep paralysis shows up explicitly in many movies like Deadwake, the TV show Haunting of Hill House and a short film called Paralysis. But often horror movies portray a scene or an experience that looks very much like sleep paralysis without labelling it as such. For example, in the movie The Conjuring, the mother struggles to sleep following her family’s move into a new house. One day she is taking a nap and midway through she wakes up with a creepy hag hovering above her. She is unable to move during this  frightening scene. And while it could be argued that she was simply experiencing sleep paralysis accompanied by a hallucination, the film presents this as the moment in which this hag invades her body and begins possessing her which pushes the haunting plot of the movie forward.

Even without a supernatural explanation, the very definition of sleep paralysis sounds like it originated from a scary story. Sleep paralysis most commonly occurs when a person is falling asleep or just waking up. If an individual has awareness as their body enters or exits REM sleep, they could experience several seconds to several minutes where they are conscious but cannot move. Because the experience is disconcerting, people often panic when it happens which makes matters worse. Sometimes paralysis is accompanied by vivid hallucinations which are likely a part of the dreams the person was having. Sleep paralysis is actually a normal part of REM sleep—it becomes a problem when it happens outside of REM sleep and the sleeper is conscious of it.

The scariest thing about sleep paralysis is that it can happen to healthy sleepers and there isn’t really a cure. Sometimes it can occur along with narcolepsy, so if you think you are regularly experiencing sleep paralysis it might be worthwhile to see a sleep specialist. Other factors that can increase the risk of sleep paralysis include: extra stress, increased or excessive alcohol consumption, narcolepsy and sleep deprivation. Sleep paralysis is also likely an originator of many so-called “hauntings” as most people who experience it report sensing a presence in the room with them even if they do not have a vivid hallucination.


Sleepwalking shows up often in horror most likely because it has also caused scary things to happen in real life: people have actually murdered other people while sleepwalking—in fact, there’s an entire defense dedicated to the phenomenon. Sleepwalking is a parasomnia, a behavior someone does while sleeping. It’s officially called somnambulism and occurs during the NREM phase of sleep, the deepest part of dreamless sleep. Unfortunately, there’s little known about why sleepwalking occurs, but it’s also not all that uncommon. Depression, anxiety, alcoholism and generalized stress can all contribute to your chances of experiencing it at some point in your life.

The mystery of sleepwalking as well as the infinite possibilities of the behaviors one could engage in while sleepwalking all figure into why it’s so frequently portrayed in horror—many ancient cultures attributed sleepwalking to divine or demonic possession, which continues to be trope in more modern media. One of the earlier scary movies which portrayed sleepwalking is the German silent film The Cabinet of Dr. Caligari in which an evil doctor uses a sleepwalking patient to commit murder. Another piece to the sleepwalking fear factor is the idea that parasomnias like sleepwalking and what we do during a period of unconscious wakefulness could be a manifestation of unconscious desires—no matter how macabre.

Nightmare Disorder

Most people have an unpleasant dream now and then, but this super rare disorder causes people to have nightmares regularly. The nightmares are so prevalent they can create major disturbances and distress during the day due to sleeplessness, result in behavioral problems and cause a fear of falling asleep.

In many horror movies, small children suffer from nightmares and/or night terrors and eventually it turns out they are ‘possessed’—perhaps this trajectory of nighttime disruption, sleep deprivation and fear of sleeping all result in devilish daytime behavior?

While not explicitly about nightmare disorder, Nightmare on Elm Street features a villain, Freddy Krueger, that kills people in their dreams and they then die in real life. Apparently the film was inspired by real life sleep problems or at least a tragic story that initially appeared to be linked to disordered sleep.

Just three years before Nightmare On Elm came out, the New York Times reported on the confusing deaths of 18 healthy Laotian refugees. In investigating the case, the Atlanta CDC considered the possibility that the refugees were scared to death by nightmares. It is unclear if nightmare disorder was actually at play here or if Brugada Syndrome was to blame. Interestingly, Brugada syndrome is more common among people of Southeastern Asian descent and while not everyone who dies of it passes in their sleep, many do and this may be one reason why sleep demons are prevalent in the mythology of Southeast Asia.

Our lack of knowledge around sleep and fears of the unexplained behaviors we can engage in while experiencing sleep paralysis, nightmares and parasomnia have all contributed to lore in ancient myths and contemporary scary films. And even when we can explain these odd sleep phenomena away, first-hand experience of them or the witnessing of others experiencing them can still leave us feeling disoriented, confused and frightened. This air of unknown makes it easy to attribute such phenomenon to the supernatural—which is why they fit right into spooky and uncanny tales of terror.


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