Sudden Unexplained Nocturnal Death Syndrome: Death by Nightmare

Updated: Sep 6, 2020

By: Nellie Nguyen

Our slumbers are occasionally disturbed by troubling nightmares that leave us in a cold sweat the following morning. The sudden awakening after a terrifying dream is often relieving—a jolt that serves as a reminder that there is no real danger. Unfortunately, the “sudden awakening” never arrived for some Southeast Asian men, and they gave their final breaths during their slumber. Dying from a dream sounds like something taken straight from the plot of a horror movie, like Freddy Krueger and the film series A Nightmare on Elm Street. However, the creator of the infamous horror franchise claimed to have been inspired by a frighteningly real incident: dozens of unexplained “nightmare deaths” of refugees from the Hmong ethnic group.

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It is commonly known as sudden unexplained nocturnal death syndrome (SUNDS), though different countries use different terms to describe these events; in the Philippines, it is called “bangungut” and in Japan, it is called “pokkuri.” The general translation for these terms usually means the same thing, which is “nightmare death.” Since April 1983, there have only been around 130 victims of the fatal disorder, all of them with relatively similar fundamental individual traits. Reported victims seemed to only be a part of certain Asian populations, including Laos, Cambodia, and Vietnam. All of the victims were young, healthy men, mostly in their 20s and 30s, who reportedly cried out right before they died– making their deaths even more puzzling. According to Kirschner, an associate professor of pathology who took a particular interest in the issue, 18 of the victims that were studied had no symptoms prior to their deaths. Additionally, regular autopsies did not reveal any reasons for their deaths except for the fact that they were caused by a sudden heart stoppage. Soon after, Dr. Friedrich Eckner from the University of Illinois College of Medicine performed a more detailed examination of the victims’ hearts. His results showed that all 18 men had slightly enlarged hearts, and 17 of them showed defects in their cardiac conduction systems. The cardiac conduction system is a group of cardiac muscle cells that send signals, carrying electrical impulses from the brain to the heart. From these results, Kirschner theorized that a random electrical discharge, which was likely caused by a nightmare, could lead to death. However, similar cases of other non-Asian populations did not show the same defect, leaving even more unanswered questions.

Referencing back to Freddy Krueger and A Nightmare on Elm Street, the creator, Wes Craven, was said to have been inspired specifically by an article from the Los Angeles Times about a refugee child from the Cambodian genocide who refused to sleep because he thought he would die from his dreams (he was one of the 130 cases of the disorder). This case is a well-known example of how terrifying the disorder can be for victims. Prior to the event, the young boy’s parents kept trying to convince him to sleep, but he insisted that if he were to sleep, he would be attacked and never wake up. Eventually, much to his parent’s initial relief, he fell asleep. Their relief was short-lived, however, as they heard him screaming in the middle of the night; he was soon found dead. The article detailing the bone-chilling incident is a great example of the disorder’s effects, and it was extremely alarming for both the Hmong ethnic group and the general public.

After lengths of research and investigation, medical professionals and the Center for Disease Control reached the conclusion that the cause for the disorder was a combination of stress and genetics. The Hmong refugees endured years of struggle in their homeland, along with the additional stress of adjusting to a different culture after immigrating to a new country. The conclusion is not entirely confirmed, and it does not really answer all questions that arose from this unsettling disorder. Unfortunately, it’s the closest that experts could get to the reason for SUNDS, but some Hmong have beliefs that the spirits of their ancestors were punishing them for leaving their homeland. Regardless, there remains no specific medical reason, and the haunting mystery of “nightmare deaths” continues on to this day.

Educational Content:

Q: What causes sudden unexplained nocturnal death syndrome? A: Also known as SUNDS, medical experts still have not been able to find a specific cause for the disorder. Experts decided that the best reasons were stress and genetics, but these still do not really provide a completely accurate explanation. A related syndrome is Brugada syndrome, which involves disturbances in the electrical system of the heart. Having this syndrome may result in sudden death, similar to the way the victims of SUNDS suddenly experienced a heart stoppage in their sleep. Additionally, the main cause for Brugada syndrome has to do with mutations of the SCN5A gene, which is a gene involved with providing instructions for making sodium channels to help with transmitting electrical signals in the body.

Q: How likely is it for someone to get SUNDS?

A: This disorder seems to only affect a very specific group of people: young Hmong men who were refugees and had recently immigrated to a new country. There have only been 130 reported cases, so luckily, it is an extremely uncommon disorder similar to other sudden death syndromes. Brugada syndrome, as mentioned previously, could result in sudden death— but only about 5 out of 10,000 people suffer from Brugada syndrome. Coincidentally, Brugada syndrome tends to be more frequent in males as well.


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