Sleep Paralysis is not yet a household word, despite the fact that 40% of the world's population reports having the experience at least once in their lives.
Still largely a mystery to medical science, Sleep Paralysis (SP) is the temporary inability to move or speak just as you are falling asleep, or just after waking up.
It's terrifying because you feel awake and alert yet do not have control over your voluntary muscles. And then it gets weird, really weird. Sometimes, sleep paralysis events include realistic hallucinations that are literally projected into the bedroom.
These are called hypnagogic hallucinations--although I personally prefer the term "visions"--and they are fully formed images, sounds and smells integrated in a sensible way with the perceived physical environment.
Lab studies have shown that, during a sleep paralysis attack, the dreamer's eyes are sometimes open, but usually they remain closed. To have this experience in the 21st century, this Age of Information, is to be cursed twice over, and many sufferers of this sleep condition are shamed into silence.
However, knowing the causes of sleep paralysis as well as the biology behind this fascinating waking dream can ease the mind and allow sufferers to "take back the night." Moreover, sleep paralysis visions can be portals to other extraordinary dream states, once the sufferer learns to control his or her fear and go with the flow.
The Nightmare, by Henry Fuseli, has long been interpreted as a depiction of sleep paralysis
Often, the hypnagogic vision is nightmarish, experienced as a hostile sensed presence in the room, or a hooded figure standing in the doorway. In a fully formed encounter, the "stranger" may sit on the dreamer's chest, holding him or her down or choking them. Sexual assault by demons and monsters are other commonly reported hallucinations.
This vision is cross-cultural, and its deep historical roots links sleep paralysis to the folklore of ghosts, goblins, succubi and vampires. In many indigenous cultures, the apparition takes the form of helpful ancestors and spirit allies, as well as the more common nightmarish entities. Sleep researchers have also connected some alien abduction reports to sleep paralysis encounters.
Keep in mind that these encounters feel real, and are remembered with crystal clarity. They do not feel like dreams in the normal sense of the word, and those who have not had experience with lucid dreaming or other altered states of consciousness believe that these encounters really happened, even though in truth the sleepers are safe and sound in bed all the while.
Lab studies have shown that sleep paralysis is a mental awakening during REM muscle atonia, which is happening every night as we dream. Without muscle atonia, we would act out our dreams, as sometimes happens with individuals who have the sleep condition known as REM Behavior Disorder. Sleep paralysis is experienced consciously due to the unusual presence of REM brainwaves during sleep onset, termed REM intrusion.
Some of the many phenomena that can occur when different sleep stages intrude upon one another.
Likewise, the dream-like imagery, including sounds, touch and smells, are correlated with REM Sleep. In other words, during sleep paralysis we literally project our REM dreams into sleep onset, while we are thinking clearly and also have some ability to sense our sleeping body and the immediate environment.
The extraordinary fear that comes with sleep paralysis may be due to the heightened activity of the amygdala, the part of the brain that controls our fight or flight responses, during dreaming sleep. Many people experience dread so intense it is called "death anxiety". Fear is also heightened due to the mish-mash of realistic dreaming imagery and actual sensed perceptions, causing our "threat vigilance system" to go haywire as the threat cannot be determined due to the ambiguity of the intruding imagery.
The danger of REM sleep, an ancient evolutionary tactic to codify learning and creative thought, is highlighted: we cannot move or respond to our environment while we are being threatened by intruders in our home. In other words, with fear in the driver's seat, we literally co-create our worst nightmares.
SP is caused by factors that interrupt our need for sleep. It is experienced by over half of those suffering from narcolepsy, and is a common symptom of sleep apnea as well. SP also happens to healthy sleepers when good sleep hygiene has been temporarily compromised, such as in sleep deprivation, jet lag and psychological factors like anxiety and grief.
For some, sleep paralysis is associated with larger, underlying causes such as post traumatic sleep disorder or generalized anxiety disorders. In the United States, African Americans appear to be more at risk, due to a higher-than-normal prevalence of anxiety disorders and social stress within the group on the whole.
College students often encounter sleep paralysis for the first time after staying up all night for an exam, or after binging on alcohol or other recreational drugs that disrupt REM sleep.
Finally, sleep paralysis can affect individuals undergoing crises of meaning or faith, a term that psychologists call a "spiritual emergency." In this way, SP may resemble a personal rite of initiation that can come at any time we are at a cross-road in life.
Despite its frightening veneer, sleep paralysis can be an opportunity to explore the world of conscious dreaming. Many people have learned to swallow their fear and use SP as a launching pad to lucid dreaming and out-of-body experiences (OBEs), which also are associated with REM sleep.
Thus, the terrifying stranger can actually transform into a helpful guide, imparting information and wisdom to the dreamer -as well as a sense of control.
Whether this information comes from the unconscious of the dreamer, or from some other uncanny source, is a matter of belief and great debate amongst psychologists and scientists.
That said, sleep paralysis is literally ground zero for exploring the neurophenomenological experience behind ghost sightings, alien encounters, and visitations by otherworldly entities around which all cultures have built mythologies and beliefs about the after-life and the structure of the universe.