People with insomnia and sleep paralysis are more likely to believe in aliens, the afterlife, and 'things that go bump in the night,' researchers find

• A study in the Journal of Sleep Research found poor sleep correlates with paranormal beliefs.
• People with insomnia and sleep paralysis more often believe in ghosts, aliens, and an afterlife.
• The study's authors told Insider the results could improve health care, but there's more to learn.

Reported sightings of ghosts, demons, and aliens are more common at night. Those who see them may have one thing in common, according to a new study published in the Journal of Sleep Research: sleep disturbances.

"People report ostensibly paranormal experiences during the night," Betul Rauf, a PhD student at the Goldsmiths University Sleep Lab who led the study, told Insider. "For some, these experiences can be terrifying which may lead to increased anxiety, and this in turn can further disturb existing sleep problems. We see that this can cause a vicious cycle."

Rauf and several other researchers were inspired to investigate the relationship between the belief in paranormal experiences on the quality of sleep "to offer an alternative explanation"  when people perceive what they think is a ghost or demon at night. The research group conducted a survey of 8,835 participants who self-reported their demographics, sleep disturbances, and paranormal beliefs.

They found that those who experience sleep disruptions like insomnia and sleep paralysis are more likely to endorse paranormal beliefs such as the soul living on after death, an ability for some people to communicate with the dead, and the existence of ghosts and demons. 

In particular, episodes of sleep paralysis and exploding head syndrome — where an explosive crashing sound in your head jolts you awake as you're beginning to fall asleep or in the middle of the night — were associated with the belief that aliens have visited earth. Sleep paralysis was also highly associated with the belief that near-death experiences are evidence of life after death. 

"It is important to note that we are only reporting on the correlations between variables and results require replication before strong conclusions can be drawn," Rauf told Insider, adding that a longitudinal study would help to prove her findings. "Although we do not provide any information about the direction of effects between variables, one possibility is that certain aspects of sleep may help to explain why some things go bump in the night. More research is required before this is clear."

Should the findings be replicated, Rauf said, the insights could potentially provide healthcare providers with important information when faced with patients reporting experiencing paranormal phenomena. The increased correlation of paranormal beliefs may be indicative of sleep disruption, for example, making the information potentially helpful for diagnosing such ailments.

"Reports of paranormal activity or anomalous beliefs could be mistaken as prima facie evidence for more severe disorders, such as schizophrenia, schizotypal personality disorder, or depression with psychotic features," reads the study. "The results provided here may encourage clinicians to assess for relevant sleep disturbances and parasomnias in addition to other forms of psychopathology. Clearly, accurate differential diagnosis could have important treatment implications."

Two in five, or roughly 40%, of Americans believe ghosts are real — and 20% say they have seen one, USA Today reported. Roughly 43% of the population believes in demons. Pew Research found belief in aliens is more prevalent, with nearly two-thirds of Americans saying there is intelligent life on other planets.

Different cultures have long contextualized sleep disturbances with explanations that range from the scientific to the supernatural. In Egypt, sleep paralysis is believed to be caused by invisible trickster genies called jinn, while in Turkey, it is the karabasan — mysterious spirit creatures — that freeze sleepers in their beds. In Italy, the state is considered an attack by the Pandafeche, described as an evil witch or menacing, giant cat. Indigenous people of South Africa believe such sleep disturbances to be caused by black magic cast by dwarfs called tokoloshe.

"People try to explain things happening through paranormal means when they can't find an explanation for things that are going on," Don Collins, a director at Fringe Paranormal, a paranormal investigator group in Ohio, told The New York Times. "Negative things are happening around them, they may tend to attribute it to paranormal activity."