科学揭秘：“鬼压床”是怎么回事？

半夜惊醒突然发现自己动弹不得、说不出话，你有过这种“鬼压床”的经历吗？“鬼压床”往往还伴随着各种解释不清的怪异现象和感觉，甚至有人自称看到了鬼。那么，真相到底是什么呢？

You jerk awake in the middle of the night in confusion. Is there a figure standing in the corner of the room? Your brain begs your limbs to move, but nothing happens. The anxiety increases. Your eyes scan the room. Just as you’re about to hit peak panic, you sit up and the figure disappears.

半夜里你突然莫名其妙地惊醒。房间的角落似乎有个人影。你想要动动四肢，但却动弹不得。你越来越焦虑。你的眼睛扫视着房间。就在你的恐慌情绪即将达到顶峰时，你坐起来了，那个人影也消失了。

You’ve just experienced sleep paralysis, one of many “parasomnias,” which is the name experts give to all sorts of weird things that occur during sleep.

你刚刚经历了睡眠瘫痪，它是众多睡眠异常的一种。专家用睡眠异常来指代睡眠时发生的各种怪异事情。

Sleep paralysis happens when the brain incapacitates the body to prevent it from acting out the vivid dreams occurring during REM (or, rapid eye movement) sleep. It often comes with a feeling of immobility, and a sense of choking.

大脑为了阻止身体对异相睡眠（或快速眼动睡眠）期的生动梦境做出回应而使身体失去活动能力时，就会发生睡眠瘫痪，常常伴随着一种无法行动的感觉和一种窒息感。

incapacitate[ˌɪnkəˈpæsɪteɪt]: vt. 使无能力；使不能；使不适于

什么是睡眠瘫痪呢？

The good news is, it’s absolutely normal. Even if it’s terrifying.

好消息是，睡眠瘫痪虽然很恐怖，但绝对是正常现象。

But when sleep paralysis happens outside of deep sleep — when a person is just dozing off or waking up — it can be “disruptive of the architecture of sleep,” said Baland Jalal, a researcher who investigates the phenomenon. That could lead to more sleep paralysis. People with poor sleeping habits experience the phenomenon more frequently.

但是，研究这一现象的科研人员巴拉德·贾拉尔说，当睡眠瘫痪发生在深度睡眠之外——例如当一个人只是打瞌睡或快要醒来时——它可能会“破坏睡眠结构”。这可能会引发更多次的睡眠瘫痪。睡眠习惯差的人则会更频繁地经历这种现象。

While the mechanisms behind sleep paralysis remain murky, Jalal said stress and worry play a part. Recent research indicates that people with anxiety and PTSD report experiencing sleep paralysis more frequently.

贾拉尔说，虽然对睡眠瘫痪背后的机制依然没有头绪，但压力和担忧是导致睡眠瘫痪的原因之一。最近的研究表明，患有焦虑症和创伤后应激障碍的人会更频繁地出现睡眠瘫痪。

“People who are anxious have much more emotional sleep. [They] are more likely to wake up during REM,” said Jalal. “If you have sleep paralysis, you probably also have anxiety.”

“焦虑的人在睡觉时受到更多情绪影响，他们更有可能在异相睡眠期间醒来，”贾拉尔说，“如果你有睡眠瘫痪的情况，那么你也很可能感到焦虑。”

The anxiety feeds into the sleep paralysis, said Jalal. People fret about experiencing the panicky feelings of sleep paralysis, which makes it more likely to occur again.

贾拉尔说，焦虑会加剧睡眠瘫痪情况的发生。人们担心会经历睡眠瘫痪的恐慌感，这反而会使它更有可能再次发生。

While about 6 percent of the population will experience sleep paralysis at one point in their lives, it occurs in about 30 to 50 percent of people with narcolepsy, a sleep disorder that includes excessive daytime sleepiness, cataplexy, sleep paralysis, and hallucinations, said Dr. Nathaniel Watson, president of the American Academy of Sleep Medicine and co-director of the University of Washington Medical Sleep Center.

美国睡眠医学研究院院长、华盛顿大学医学睡眠中心联合主任纳撒尼尔·沃森博士说，虽然大约6%的人一生中会在某个时候经历睡眠瘫痪，但大约30%到50%的嗜睡症患者中会出现睡眠瘫痪。嗜睡症的症状包括白天过度困倦、昏睡、睡眠瘫痪和出现幻觉。

narcolepsy[ˈnɑːrkoʊlepsi]: n. 嗜睡症；发作性睡病

Students are more likely to experience sleep paralysis with as many as 28.3 percent of students reporting it.

报告显示，学生更有可能出现睡眠瘫痪，比例高达28.3%。

Some people report the feeling that someone or something is trying to strangle or choke them or will see someone coming into their room and not able to move or scream, experts say. It can also happen when the person is awake, lasting from a few seconds to a minute or two. It's associated with hypnagogic hallucinations, which occur as a person is falling asleep.

专家称，有些人报告说，睡眠瘫痪的感觉就像有人或者有东西在试图把他们勒死或掐死，又或者是看到有人进到了房间里，但他们却无法移动或者叫喊。睡眠瘫痪也有可能发生在人醒着的时候，过程会持续几秒到一两分钟。它与催眠幻觉有关，通常发生在人睡着的时候。

For most people, “it is not indicative of any kind of disease,” said Watson. While the experience feels frightening, the episodes last only a few seconds or minutes at most.

沃森博士说，对于大部分人来说，“睡眠瘫痪并不意味着任何疾病”。尽管这种经历很恐怖，但是它每次只会持续几秒，最多几分钟。

Most people slip out of it as quickly as they fell into it. A light touch from a partner can be enough to stop it, he said.

他说，大部分人一进入睡眠瘫痪就能够抽身而出。伴侣的轻轻触碰就可以阻止睡眠瘫痪的持续。

鬼魂是真实存在的吗？亦或是一种睡眠幻象？

While not everyone who has sleep paralysis experiences hallucinations, seeing a person or a ghost in the room is the most common vision, said Jalal.

贾拉尔说，并不是每个人都在睡眠瘫痪时出现幻象，最常见的幻象是看到房间内有人或有鬼。

Hallucinations vary by culture — the Chinese call it “guiya” or ghost pressure because they believe a ghost sits on people’s chests. In Newfoundland, it is the “old hag” because people see a witch and in Egypt people see Jinn (what Westerns call genies), which are known to hunt and sometimes kills their victims.

这种幻觉因文化而异——中国人称之为“鬼压床”，因为他们相信鬼怪会坐在人们的胸膛上。在纽芬兰，人们称之为“老巫婆”，因为人们出现的幻觉里有一个巫婆。在埃及，人们看到的是精灵，精灵以狩猎闻名，有时会杀死他们的猎物。

These ghostly "waking dreams” can involve serpents, spiders, intruders and even ghosts. They're often associated with feelings of dread.

这些幽灵般的“醒梦”内容可能涉及蛇、蜘蛛、入侵者甚至鬼魂。它们常常与恐惧感联系在一起。

Some experts have suggested that alien abductions are really just intense bouts of sleep paralysis.

一些专家指出，所谓的外星人劫持其实只是睡眠瘫痪的剧烈发作。

“When you live in a culture where you are afraid of it, you are much more likely to be anxious [about sleep paralysis] and experience it,” Jalal said.

贾拉尔说：“当你身处在自己所惧怕的文化氛围中，你就更有可能经历睡眠瘫痪，并对其感到焦虑。”

Sometimes an environmental reason is the cause of the spectral vision.

有时，环境因素也会引发鬼怪的幻觉。

In 2005, the Journal of Emergency Medicine reported about a 23-year-old woman who was found delirious and hyperventilating after seeing a "ghost".

2005年，《急诊医学杂志》报道了一名23岁的女人，她在看到“鬼魂”后出现精神错乱和呼吸急促的症状。

“On arrival in the ED (about 30 minutes later), the patient was still hyperventilating but was able to talk. She denied taking illicit drugs or alcohol but recalled seeing a ghost while taking bath,” the researchers wrote.

研究者写道：“到达急诊室时（大约30分钟后），患者仍然呼吸急促，但她能够讲话了。她否认服用违禁药物或酒精，但她回忆说洗澡时看到了鬼。”

It was later determined that her new gas water heater had been improperly installed and her house was filled with carbon monoxide. After oxygen therapy, she made a full recovery.

后来确定了是她的新燃气热水器安装不当，导致她的房子里充满了一氧化碳，她才会产生这种幻觉。经过氧气治疗后，她就完全康复了。