Horror movies based on true events are even creepier after you hear the real-life tale, and Nightmare on Elm Street is no exception. The story of the infamous, striped-sweater-wearing maniac was not just the invention of writer/director West Craven; the movie is actually based on real-life events. As is often the case with violent movies based on true stories, the real inspiration for Freddy Krueger is pretty disturbing.
In 1977, well over 100 Laos refugees inexplicably died in their sleep. The deaths of these perfectly healthy Hmong men have since been attributed to cardiac arrhythmia, but superstitious Lao people blame dab tsuam, an evil spirit that kills you in your sleep, and who appears in the form of a jealous woman.
The phenomenon was labeled "Sudden Unexpected Nocturnal Death Syndrome" (SUNDS), a term that was coined after healthy men all over the world began mysteriously dying in their sleep. If Freddy gives you nightmares, you don't even want to begin thinking about dab tsuam.
Ly Houa, a Hmong medic living in America, is thought to be the first victim killed by what was originally called "Asian Death Syndrome." After he died in his sleep in 1977, a social worker who knew him was surprised, as he was physically active and in good health.
Houa's death was reported by the LA Times, who went on to cover 20 similar stories over the course of the next four years. The victims were primarily men who shared a median age of 33, and who were generally known to be healthy. It was reported that several witnesses heard the victims emit groans or experience breathing trouble for a short while before their deaths.
Others claimed to have heard victims speak of having nightmares several nights prior to their deaths. In 1981, 26 Hmong men — most of whom were refugees — died in their sleep, causing the Federal Center for Disease Control to label their cause of death Sudden Unexpected Nocturnal Death Syndrome (SUNDS). According to the Orange County Medical Examiner, half the total deaths of Hmong people during that time period are attributed to SUNDS.
Along with Filipinos, many Hmong people believe in a spirit called "dab tsuam" or "dab tsog" who takes the form of a jealous woman and visits men while they sleep. These malicious spirits trap and crush their victims in a manner similar to the hallucinations sometimes experienced by those who suffer from sleep paralysis. The dab tsuam visit people who don't honor their ancestors and the spirits who guard their village, and they're also said to show up if a person performs a ritual poorly. Many men are believed to dress up as women when they go to bed in order to trick the dab tsuam.
Some researchers have suggested that the mysterious deaths may be related to sleep paralysis, which occurs when the mechanism that forces people to refrain from physical activity while sleeping doesn't turn off after an individual wakes up.
A sleep paralysis victim is fully awake, but completely unable to move. To make things worse, many experience scary hallucinations during their paralysis, such as shadow people, or an old hag who pins her victims down by sitting on their chest. Scientifically, these are considered to be hypnopompic hallucinations leftover from the person's dream-state.
These hallucinations are referred to as "tsog tsuam" by the Hmong people, and are thought to plague those who do not respect their ancestors. It's possible that the Hmong victims were so terrified of being visited by evil spirits that they unknowingly willed themselves to die. This phenomena is known as the nocebo effect, which works similarly to the placebo effect. By focusing intensley on negative thoughts, one's worst nightmares eventually come true.
At the time of the 1977 SUNDS outbreak, there were only about 35,000 Hmong people living in America, making the amount of people affected by the syndrome seem monumental. However, similarly mysterious deaths had been common in several Asian countries for years, and many of these victims weren't Hmong.
Such deaths have occurred in places like the Philippines, Thailand, and Japan. More than 500 Japanese men were believed to have died as a result of "Pokkuri," and 230 healthy Thai men succumbed to death during sleep between 1982 and 1990. "Bangungut" curses the people of the Philippines, and is thought to be responsible for the deaths of 43 out of 100,000 Filipino people every year.
Many of the mysterious deaths in Thailand were attributed to stress brought on by working under harsh conditions for upwards of 13 hours a day, suggesting that the plague is brought on by more than just genetics.