It is an affliction as old as the human mind, a condition estimated to effect 10% of the population at some point in their lives.

Sleep paralysis.

The scenario usually plays out in this way.

You wake up in the middle of the night, unable to move. As you lie in bed helpless, you feel like someone (or something) is in the room with you. An intruder. You try to move, but you are weighed down. Unable to respond. To even take a breath.

Henry Fuseli’s The Nightmare (1781) is perhaps one of the most famous depictions of this strange affliction.

 A woman is captured in full swoon with a nasty creature perched on her chest.

In Fuseli’s version, the nightmare attacker is a demon. In fact, one of the Western words for demon-incubus- comes from the Latin “to lie upon”, the very sensation that defines the condition.

The form the monster takes depends on the culture. In Europe and Africa, it can be a witch-like hag. In the Middle East, a djinn. In the United States, the nighttime visitor is often portrayed as an extraterrestrial, an alien from the far reaches of space.

So what exactly is going on?

Sleep paralysis occurs at a specific spot in the dream cycle. Every night, we move through several states of consciousness—from awake, to dozing, to deep sleep, to vivid dreaming. When we are in a deep dream state, our muscles are completely paralyzed (except for our eyes and respiratory system). This is our body’s attempt to to keep us from acting out our dreams and injuring ourselves. Most of us transition between these stages without waking up. But some people jump from their REM state to being fully awake before their body has a chance to reactivate, in what is known as the SOREM period.

This results in the horrible sensation of being trapped, pinned to the bed by an unseen entity. Sleep paralysis can last anywhere from a few seconds to one to two minutes. But every moment seems like a lifetime...

Photographer Nicolas Bruno, who suffers from sleep paralysis, has given us a vivid, modern depiction of the condition. Inspired by 19th century Romanticists, his photographs capture the terror of being caught between two worlds. Of being caught in a liminal space. A sleeper awake.

Interested in extra-credit? Here’s more on sleep paralysis.