Nightmares: why you have them, what they mean and what the traditions say

A nightmare is a dream frightening enough to wake you, and almost everyone has them. Most are about tension, change or something you have not yet processed; none of them predicts what will happen. This guide explains why nightmares come, which ones people have most, how eleven traditions read them, what you can do in the night and the morning after, and when it is wise to look for help.

In short

A nightmare is a dream frightening enough to wake you; almost everyone has one now and then.
They usually arise in REM sleep and are linked to stress, change, too little sleep or something not yet processed.
None of the traditions on this site reads a nightmare as a prediction; Islam does not interpret a bad dream at all.
If they come several times a week or after something traumatic, talk to your doctor: effective treatments exist.

What a nightmare is, and what it is not

A nightmare is a vivid, frightening dream that wakes you up, usually in the second half of the night, and that you remember clearly. Your heart is racing, and for a moment the dream still feels real. That last part is what sets it apart from a bad dream: a bad dream is unpleasant, but you sleep through it.

Two other night experiences are often confused with it. Night terrors (pavor nocturnus) mostly happen to children, early in the night and in deep sleep: the child screams or sits up, seems awake but is not, and remembers nothing the next morning. Sleep paralysis is the moment of waking up and being unable to move for a few seconds, sometimes with the feeling that someone is in the room. It is common and harmless, and it deserves its own explanation: see our guide to sleep paralysis.

Nightmares are very common. Studies suggest that most adults have at least one a year, that a sizeable minority have one every month, and that a small group, roughly two to six in a hundred, have them every week. In children between about three and ten they are more frequent still, and for most they fade with age.

The word itself carries an old story. The second half of nightmare, like the Dutch nachtmerrie, does not come from the horse but from the mare, a night spirit in Germanic folk belief that was said to sit on a sleeper's chest and press the breath out of them. That is folklore, but it shows how long people have tried to explain the weight they feel when they wake from a frightening dream.

Why you have nightmares: what dream research says

Most dreaming, and almost all nightmares, happens in REM sleep, the phase in which the brain is very active and the body is held still. In REM sleep the brain reworks the impressions and emotions of the day. Researchers think that dreams help to file experiences and to take the sharpest edges off feelings. A nightmare is then what happens when that processing gets stuck: the feeling is too strong, and the dream wakes you before it is done.

That explains why nightmares come in clusters. They are more frequent during stress, at times of change such as a move, a new job, a breakup or an exam period, and after a loss. Illness and fever play a part, and so do some medicines, alcohol and stopping certain medication or substances, because they change REM sleep. Too little sleep makes them more likely too: after a short night the brain catches up with extra REM sleep, which is more intense. Eating late is often blamed; the evidence for that is modest, but a restless body does sleep more lightly.

After a frightening or traumatic experience, nightmares can keep replaying the event, sometimes almost literally. That is a different matter from the occasional bad night, and we come back to it in the section on when to look for help.

Not everyone is equally prone to them. The American psychiatrist Ernest Hartmann, who studied people with frequent nightmares, found that many of them were unusually open and sensitive, with what he called "thin boundaries": they felt things strongly, were often creative, and let the day in deeply. Seen that way, frequent nightmares say less about something being wrong with you than about how intensely you take in the world. The body plays a part too: being too warm, a full bladder, or breathing that stops and starts during sleep can all make dreams more frightening.

There are also theories about why we dream of danger at all. The Finnish researcher Antti Revonsuo proposed in 2000 that dreams simulate threats, so that we rehearse escape and defence in a safe setting. It is one theory among several, not settled fact, but it fits a striking observation: across cultures, people mostly dream of being chased, falling, losing control or being too late. In that light a nightmare is not a malfunction, but a mind practising, sometimes too hard.

The nightmares people have most

Some nightmares come back in almost every culture. Each has its own page on Dreamkin, where traditions read the image side by side; here is what they usually touch on.

Being chased is the classic: something or someone is after you, and you cannot get away. It often points to something you are avoiding during the day, a conversation, a decision or a feeling. Falling tends to come in periods when you feel you are losing your grip, and the jolt awake just before the ground is partly physical. Dreams of losing teeth are linked with tension, with how you come across, and in research with tension in the jaw.

Dying in a dream, your own death or someone else's, frightens many people, but almost no tradition reads it literally: it is far more often about an ending or a change. A deceased loved one who appears in a frightening way usually belongs to grief that is still at work.

Then there are the dreams of failing. Being late or missing a train, an exam you have not prepared for, years after school, and being naked in public: they touch on the fear of falling short, or of being seen as you are.

Some images carry a threat from outside. A snake that attacks, water that rises or a feeling of drowning, war, being locked up in prison, or an earthquake that shakes the ground: they often come when something in your life feels bigger than you, or when you feel trapped in a situation.

A last group deserves a mention because it frightens people so much: nightmares in which something happens to someone you love, a child who goes missing, a partner who is hurt. They are especially common in new parents and in people caring for someone. They express how much is at stake for you, and the fear of losing it; they are not a warning about that person.

What these dreams share is that the feeling says more than the image. Two people can dream of the same snake; one wakes frightened, the other curious. That feeling is the best way in, and the table below shows how differently the traditions read it.

Nightmares in the traditions at a glance

How each tradition sees a frightening dream, where it may come from, and what people usually do.

Tradition	What a nightmare is	Where it may come from	What people do
Islam	Hulm, a disturbing dream; not interpreted	Shaytan, or one's own worries	Seek refuge in God, spit left three times, tell no one
Judaism	A letter that asks to be read	The day's thoughts, or a warning	Hatavat chalom before three friends; sometimes a fast
Christianity	Not a verdict; something to be comforted in	Cares, grief; some churches say spiritual attack	Prayer, Psalms, talking to someone trusted
Winti	A sign that something asks attention	A winti or ancestor (yorka); imbalance in the family	Discuss within the family or with an expert
Vodou	A message from the unseen world	A neglected lwa or ancestor	Remember the ancestors; ask within the house
Santería	A signal, never the last word	The egun, the dead, asking attention	Divination with a padrino or madrina
Akan	A warning or reminder	The nsamanfo, the ancestors	Talk it through with an elder
Hinduism	Weighed by the hour of the night	Restless doshas, or a sign	Prayer; a dream near dawn counts more
Buddhism	The mind's fear taking shape	Habit, craving and fear	Metta before sleep; look at the fear
Chinese (Zhou Gong)	Often read by contraries	Imbalance, or a sign of the opposite	Read the image within the family
Wicca	A shadow that wants to be seen	A part of yourself you avoid	Shadow work; turn and face it

Traditions differ by family, house and region.

What the traditions say: Islam, Judaism and Christianity

Islam distinguishes three kinds of dream, a distinction that goes back to a hadith in Sahih Muslim, among other collections. The ru'ya is the good, true dream; the hadith an-nafs comes from your own thoughts and worries; and the hulm is the disturbing dream, attributed to Shaytan. A nightmare usually falls in that last category, and the tradition is clear about what that means: it is not to be interpreted. The hadith collections of al-Bukhari and Muslim describe what to do instead: seek refuge in God from the evil of the dream, spit lightly to the left three times, turn onto your other side, and do not tell the dream to anyone, because then it will not harm you; some narrations add that one may get up and pray. In folk belief a nightmare, kabus in Arabic, is sometimes linked with djinn. The tradition describes djinn as real beings, but reading them into every bad dream is a step many scholars warn against. Our guide to ta'bir al-ru'ya explains the three kinds of dream in more depth.

Judaism takes a frightening dream seriously without fearing it. The Talmud says that "a dream that is not interpreted is like a letter that is not read" (Berachot 55a). For a dream that troubles you, it describes hatavat chalom, having the dream "made good": the dreamer speaks before three friends, who answer with words of blessing (Berachot 55b). Classical sources also know ta'anit chalom, a fast after a disturbing dream. Both turn a solitary fear into something shared and spoken aloud.

In Christianity a nightmare is above all not a verdict. The Bible itself tells of frightening dreams, from Job to Pilate's wife, and the most common Christian answer is comfort and prayer: Psalm 4 ends with "in peace I will lie down and sleep". Some churches, especially in charismatic and Pentecostal circles, speak of spiritual attack; Catholic, Orthodox and many Protestant traditions are more cautious. Our guide to nightmares in the Christian tradition goes into this in detail.

What the traditions say: Winti, Vodou, Santería, Akan and the East

In Winti a nightmare is not simply waved away. Families and experts in the tradition may read a frightening dream as a sign that a winti or an ancestor, a yorka, is asking for attention, or that something in the family is out of balance. What is read into it, and what should be done, is decided within the family or with someone knowledgeable, not from a dream dictionary. Some families also speak of harmful influence, such as wisi; that is a belief some people hold, not something a dream proves. Our guide to how Winti reads a dream explains the approach.

In Vodou, Santería and Akan tradition the dead and the spirits announce themselves in dreams too. In Haitian Vodou a frightening dream can be read as a lwa or an ancestor who feels neglected; in Santería the egun, the dead, may be asking to be remembered, and what a dream means is established through divination, never from the image alone; among the Akan the nsamanfo, the ancestors, can appear in dreams as a warning or a reminder. In all three the answer to a nightmare is less "what will happen" than "who is asking for attention, and what is unfinished". See Vodou and dreams, the Orishas and dreams and Akan dreams.

Hinduism knows the dream as one of the states of consciousness the Upanishads describe, between waking and deep sleep. In folk belief and in many texts, a dream in the last part of the night, just before sunrise, weighs more than one early in the night, so a nightmare at midnight is taken less seriously than one at dawn. Ayurveda links frightening, restless dreams with an imbalance of the doshas. Many families find comfort in a prayer, for example to Hanuman, who is seen as a protector against fear.

Buddhism sees dreams as the mind continuing its habits in sleep, and nightmares as fear and craving taking shape. The Buddha names, among the benefits of loving-kindness, metta, that one sleeps easily and dreams no evil dreams; many Buddhists therefore practise metta before sleep.

The Chinese dream books associated with Zhou Gong often read frightening dreams by contraries: dreaming of death would mean a long life, dreaming of weeping a reason for joy. That is a tradition of reading, not a guarantee. Wicca, finally, tends to see a nightmare in the light of shadow work: the frightening figure is often a part of yourself that wants to be seen.

What you can do after a nightmare

In the first minutes, the aim is simply to come back to the present. Turn on a soft light. Breathe out slowly, longer than you breathe in, a few times. Put your feet on the floor and name three things you can see in the room; it sounds simple, but it tells your body that the danger is over. If you can, avoid picking up your phone to read the news or scroll: the mind is still looking for threats, and it will find them.

If the dream keeps going round in your head, write down a few lines, or say out loud what it was about. Many people find that a fear named is a fear that shrinks. In the morning it helps to write the dream down properly, with the feeling and the details. Our guide to remembering your dreams explains how to keep a dream journal.

For a nightmare that keeps coming back, there is a well-researched exercise: rewrite the ending. During the day you write the dream down and change it, anywhere you like, into a version that ends differently, and you go over the new version for a few minutes a day. This is the principle behind imagery rehearsal therapy, which psychologists use for recurring nightmares and which has been tested in studies since the 1990s. You can try the basic idea yourself; for heavy or trauma-related nightmares, do it with a professional.

Sleep habits help more than people expect: regular times, enough sleep, less alcohol in the evening, and no frightening films or work emails right before bed. They do not prevent every nightmare, but they make the nights calmer.

And every tradition has its own comfort. Some people pray, some light a candle, some say a verse or a name that means protection to them, some simply hold someone's hand. The sections on the traditions above describe what each of them does; what helps you is yours to choose.

Nightmares in children

Children have more nightmares than adults, most often between about three and ten, when imagination grows faster than the ability to tell it apart from reality. A monster under the bed, being lost, an animal that bites: the images are simpler, but the fear is just as real.

What helps is mostly calm and closeness. Go to your child, listen, and say that it was a dream and that they are safe now; a night light or an open door can make going back to sleep easier. During the day, not at bedtime, you can talk about the dream, or let your child draw it and then draw something that makes it less frightening: the monster gets a funny hat, or a friend comes to help. That is the same principle as rewriting the ending for adults. Frightening films, games and news just before bed are best avoided.

Night terrors are different: the child is not really awake and will not remember it. Do not try to wake them; stay close, keep them safe, and let it pass. If nightmares or night terrors keep going on for weeks, or a child becomes afraid to go to bed, mention it to your GP or child health clinic.

Interpreting a nightmare

The question most people ask after a nightmare is "what does it predict?". The more useful question is "what does it touch on?". A nightmare almost never says something about the future; it says something about what is weighing on you now.

Three questions help. What did you feel in the dream: fear, shame, powerlessness, anger, grief? That feeling is usually the core. What is going on in your life at the moment that carries the same feeling, even if it looks nothing like the dream? And which image stood out, the one you still see when you close your eyes? That image is the dream's way of giving the feeling a shape.

Then look at how the dream ended, or where it broke off. Did you escape, were you caught, did you wake just before something happened? The place where you woke up often marks exactly the point you find hardest during the day.

An example. Someone dreams that they are in their old school, an exam is about to start, and they cannot find the room; they wake just as the door closes. The feeling is panic and not being prepared. In their life, a performance review at work is coming up next week. The image of the closing door is the moment they fear: being judged before they are ready. Read like that, the nightmare is not a prediction that it will go wrong, but a pointer to what they could prepare, or say, before then.

Our guide on how to interpret a dream takes you through this in eight steps, and if the same nightmare keeps returning, our guide to recurring dreams explains what that repetition usually asks of you.

When to look for help

An occasional nightmare is part of life. It is wise to talk to your GP or a psychologist if nightmares come several times a week, if you are afraid to go to sleep, if they keep replaying something that really happened, or if they leave you exhausted, anxious or irritable during the day. Effective treatment exists, such as imagery rehearsal therapy and trauma-focused therapy.

For children: frequent nightmares or night terrors are worth mentioning to your GP or child health clinic, especially if they disturb sleep for weeks.

It can help to keep a short note for two weeks before the appointment: how often the nightmares come, what they are about, and what happened that day. That gives your doctor a much clearer picture than "I sleep badly".

If nightmares come with thoughts of not wanting to live, do not wait: contact a doctor or a crisis line. In the UK you can call Samaritans on 116 123, in the US you can call or text 988, and elsewhere your local emergency number or crisis line.

Keeping track in your Dream Book

A single nightmare is a moment; a nightmare that returns is a pattern, and patterns become visible only when you write them down. In the Dreamkin app you can record every dream, including the frightening ones, and have it read in the tradition that matters to you. After three dreams your Dream Book opens its first chapter, and over time you see which images and feelings keep coming back, and when they fade.

Dreamkin does not diagnose and does not predict. What the app does is keep your dreams together in one private place, so that you, and if you want the tradition you choose, can look at them with a little distance. Many people find that a nightmare loses some of its power once it is written down beside the calmer dreams that came before and after it.