Four out of every five people in Ireland have had at least one episode of sleep paralysis, according to research carried out by the School of Psychology at NUI Galway.
Sleep paralysis is an often disturbing sleep experience where people feel like they are in an awake-like state.
The study, which gathered the sleep experiences of more than 1,100 people, aimed to examine how individuals' lifestyle and emotions are connected to their sleep, as well as looking at sleep issues like paralysis.
Almost one in five people said they had gone through sleep paralysis between one and three times in their lives, and the same proportion had also had between four and ten episodes.
However, over a quarter said they had experienced sleep paralysis more than 20 times.
The often distressing phenomenon typically happens as people are falling asleep or waking up.
The people who took part in the study described a range of symptoms, including sensing there is someone in the room, or seeing demons and intruders with no face, and being unable to scream.
Around a third of those who said they suffered from the problem also said they had experienced mental health issues during their lives.
One sixth said they currently had mental health challenges.
