Vampires, ghosts and demons: the nightmare of sleep paralysis

Tales of things that go bump in the night have existed for centuries, but they may in fact be part of a surprisingly common neurological phenomenon

It's known as "Ghost Depression" in China, "Kanashibari" in Japan, meaning to be bound or fastened by metal strips, and "Karabasan" or 'The Dark Presser' in Turkey. The latter sounds oddly like a 1980s metal band, but these three terms all refer to the same thing - the often terrifying and little understood ordeal of sleep paralysis, which is believed to have left various imprints on our culture throughout the millennia, from tales of ghosts in the night to visits from aliens.

Over the past few months, sleep paralysis has made its way to the big screen for the first time in the shape of new docu-drama The Nightmare. With the help of a variety of special effects, director Rodney Ascher brings to life the often terrifying bedtime experiences suffered by individuals around the world. And they're more common than you might think. Studies suggest that around 8% of the general population, 28% of students and 32% of psychiatric patients have experienced sleep paralysis at least once.