Nightmares vs Night Terrors: What's the Difference?
The short answer
Nightmares vs night terrors comes down to sleep stage and memory. A nightmare is a frightening dream from REM sleep that wakes you and that you remember. A night terror, or sleep terror, comes from deep non-REM sleep: the person may scream or sit up in fear, is hard to comfort and usually remembers little or nothing.
In this article
Two very different things get called “a bad night.” In one, you wake up gasping from a dream about being chased and can describe every detail. In the other, someone sits bolt upright and screams, eyes open but not really there, and in the morning remembers nothing. The first is a nightmare. The second is a night terror. Knowing which one you are dealing with changes almost everything about how to respond.
Nightmares vs night terrors: the core difference
The clearest way to understand nightmares vs night terrors is to look at three things: when in sleep they happen, what the person remembers, and how they behave.
Sleep stage. Nightmares come from REM sleep, the stage linked to vivid, story-like dreaming. Night terrors come from deep non-REM sleep, the heaviest and least dreamlike stage.
Memory. After a nightmare, you remember a dream, often in detail: what happened, who was there, what you felt. After a night terror, the person usually remembers little or nothing.
Waking. A nightmare wakes you up, and you become alert fairly quickly. You know where you are and can be comforted. During a night terror, the person is not properly awake. They may look awake, but they are hard to reach and may be confused if woken.
Behavior. Nightmares mostly happen inside your head; you might whimper or move a little, then wake. Night terrors are typically described as dramatic: a sudden scream, sitting up, a racing heart, sweating, sometimes thrashing or trying to get out of bed.
Put simply: a nightmare is a frightening dream you remember; a night terror is a frightening episode the person usually does not remember.
What sleep science says about nightmares and sleep terrors
The definitions used by clinicians come from the International Classification of Sleep Disorders (ICSD-3), published by the American Academy of Sleep Medicine. It describes nightmare disorder as involving frightening dreams from REM sleep that are remembered, and sleep terrors as episodes arising from deep non-REM sleep that are usually not remembered. That stage difference is the backbone of the distinction.
The link between REM sleep and vivid dreams goes back to 1953, when Eugene Aserinsky and Nathaniel Kleitman discovered regular bursts of rapid eye movement in sleep and found that people woken from them usually reported vivid dreams. That is why a nightmare arrives with a full plot.
Later research complicated the neat REM-equals-dreaming picture. A 2017 study led by Siclari found that dreaming happens in both REM and non-REM sleep. So non-REM sleep is not dreamless, which helps explain why some people recall a single image or feeling after a night terror. But the developed, remembered story is the hallmark of a nightmare, not a sleep terror.
Nightmares themselves have been studied in depth. Levin and Tore Nielsen’s review proposes that nightmares reflect failures of fear extinction during dreaming, and that affect distress - how upset you are by your dreams - drives how much people suffer from them. And there is a well-tested way to reduce them: in a randomized trial led by Barry Krakow, people who rewrote a recurring nightmare while awake and rehearsed the new version had fewer nightmares.
A third state often gets confused with both. In sleep paralysis, also defined in the ICSD-3, you wake up unable to move, sometimes sensing a presence in the room. A systematic review by Sharpless and Barber found that a meaningful minority of the general population has had sleep paralysis at least once.
How to tell them apart: common scenarios
Real nights are messier than definitions. These scenarios show how the difference plays out.
You wake up and remember a scary dream
You were being chased, a loved one was hurt, you were trapped. You wake with your heart pounding and can describe the dream. This is a nightmare. If it happens often, our guide to nightmares every night covers causes and what helps.
Your partner says you screamed, but you remember nothing
You apparently sat up, shouted, maybe looked terrified - and you have no memory of it, or only a vague sense of fear. This pattern fits a sleep terror rather than a nightmare.
A child screams and cannot be comforted
A young child sits up screaming, eyes open, but does not seem to recognize you and pushes you away. After a while they settle and go back to sleep, and in the morning they have no idea anything happened. This is the classic picture of a night terror in childhood, and it is often more frightening for the parent than for the child.
A child wakes scared and tells you the dream
“There was a monster in the closet.” The child is awake, wants comfort, and can describe what happened. That is a nightmare. Comfort works, and talking about the dream the next day can help.
Nightmares vs night terrors in adults
Adults have nightmares at every age. Night terrors in adults are less common and are typically described as dramatic, sudden and poorly remembered. If an adult starts having episodes of screaming or thrashing they do not recall, that is worth discussing with a doctor.
Waking up frozen with a presence in the room
You are awake, aware of the room, but cannot move, and you may feel or see something frightening nearby. This is sleep paralysis, not a nightmare or a night terror. See lucid dreaming vs sleep paralysis for how it compares with other states at the edge of sleep.
Waking in tears without a clear dream
You wake crying with only a feeling left. This can follow a nightmare whose story faded, a common experience covered in why you wake up crying from dreams.
| Feature | Nightmare | Night terror (sleep terror) |
|---|---|---|
| Sleep stage | REM sleep | Deep non-REM sleep |
| Memory afterwards | Clear dream, often detailed | Little or none |
| Waking | Wakes up and becomes alert | Hard to wake, confused |
| Typical behavior | Little movement, then waking | Screaming, sitting up, thrashing |
| Can be comforted | Yes, once awake | Often not during the episode |
| Typical age | Any age | More typical of childhood |
| What helps most | Understanding and rewriting the dream | Safety, calm, medical advice if frequent |
Context changes the picture
The label matters less than what the episodes are doing to your life, or your child’s.
Age. In children, night terrors are a well-known part of childhood sleep, and many children have fewer of them as they get older. In adults they are less typical, and a new pattern deserves a conversation with a doctor.
Frequency and safety. A rare episode is usually just that. Frequent episodes, episodes that lead to injury, or anything that involves leaving the bed or the house are reasons to get medical advice.
Distress. For nightmares, the key question is how much they affect you. A scary dream now and then is part of normal dream life; nightmares that leave you dreading sleep are not something to just put up with.
What is going on. Stress, short sleep and big changes are commonly linked to both nightmares and night terrors. Looking at the bigger picture - work, sleep schedule, recent events - often shows what is feeding the episodes.
If nightmares or night terrors keep you or your family from sleeping or living well, it is worth talking to a doctor or a therapist. For a child, a pediatrician is a good first step.
The spiritual and cultural view
Long before sleep labs, people tried to explain both experiences. Many cultures described a night visitor who sits on the chest or haunts the bedroom - the English “nightmare” itself comes from the “mare”, such a spirit. Children’s night terrors have been attributed in various traditions to spirits, the evil eye or a frightened soul, and families developed protective rituals, prayers and objects to keep children safe at night.
These explanations make sense when you consider how strange night terrors look: a child awake but not awake, terrified of something no one can see. For many families, rituals offered comfort and a sense of control, and they can still be meaningful today.
The scientific view adds something practical. Knowing that a night terror comes from deep sleep, and that the child usually will not remember it, can take a lot of fear out of the experience for parents. Knowing that a nightmare is a remembered dream opens the door to understanding and changing it.
What to do after a nightmare or a night terror
The right response depends on which one it was.
- For a nightmare, write it down. Note the main image, the feeling and any link to your day. A remembered dream can be understood, and that alone often makes it less powerful.
- For a recurring nightmare, rewrite it. Create a new version of the dream while awake and rehearse it for a few minutes a day. This is the approach that reduced nightmares in Krakow’s trial.
- For a night terror, focus on safety. Stay nearby, keep the person from bumping into furniture or stairs, and let the episode pass. Trying to talk them out of it usually adds confusion.
- Do not quiz anyone in the morning. After a night terror, there is often nothing to remember. Questions can make a child anxious about sleep.
- Look at sleep and stress. Regular sleep times and enough sleep help with both nightmares and night terrors. If you dream intensely in general, why your dreams are so vivid explains common drivers.
- Get medical advice when it fits. Frequent episodes, any injury, new night terrors in an adult, or nightmares that follow trauma are all reasons to see a doctor or a therapist.
Nightmares vs night terrors can look alike from the outside, but they are different experiences. One is a dream you can work with; the other is an episode to keep safe through.
Frequently asked questions
What is the difference between nightmares vs night terrors in adults?
In adults the core difference is the same as in children. A nightmare is a remembered, frightening dream that wakes you from REM sleep, and you are quickly alert. A night terror happens in deep non-REM sleep, often with screaming or sudden movement, and the person usually does not remember a story. Night terrors in adults are less common and are worth discussing with a doctor.
Are nightmares vs sleep terrors the same as nightmares vs night terrors?
Yes. Sleep terrors is the clinical term used in the International Classification of Sleep Disorders, and night terrors is the everyday name for the same thing. Both describe episodes of intense fear arising from deep non-REM sleep, as opposed to nightmares, which are remembered dreams from REM sleep.
Can you remember a night terror?
Usually not, or only a fragment. Because night terrors arise from deep non-REM sleep rather than from a dream in REM, the person typically has little or no memory of the episode in the morning. Some adults recall a single frightening image or feeling, but not the developed story that people remember after a nightmare.
Should you wake someone having a night terror?
It is usually hard to wake someone from a night terror, and trying to shake or talk them out of it often leads to more confusion. Common guidance is to stay close, keep them safe from bumping into things and let the episode pass. If night terrors are frequent, dangerous or new in an adult, talk to a doctor.
Do children have more night terrors than adults?
Night terrors are generally described as more typical of childhood, and many children have fewer of them as they get older. Nightmares, by contrast, happen at every age. If a child's night terrors are frequent, cause injury or worry you, a pediatrician is the right person to ask. Adults with new night terrors should also speak with a doctor.
Sources
- American Academy of Sleep Medicine. (2014). International Classification of Sleep Disorders (3rd ed.). American Academy of Sleep Medicine.
- Aserinsky, E., & Kleitman, N. (1953). Regularly occurring periods of eye motility, and concomitant phenomena, during sleep. Science, 118(3062), 273-274.
- Siclari, F., Baird, B., Perogamvros, L., Bernardi, G., LaRocque, J. J., Riedner, B., et al. (2017). The neural correlates of dreaming. Nature Neuroscience, 20(6), 872-878.
- Levin, R., & Nielsen, T. A. (2007). Disturbed dreaming, posttraumatic stress disorder, and affect distress: A review and neurocognitive model. Psychological Bulletin, 133(4), 482-528.
- Krakow, B., Hollifield, M., Johnston, L., Koss, M., Schrader, R., Warner, T. D., et al. (2001). Imagery rehearsal therapy for chronic nightmares in sexual assault survivors with posttraumatic stress disorder: A randomized controlled trial. JAMA, 286(5), 537-545.
- Sharpless, B. A., & Barber, J. P. (2011). Lifetime prevalence rates of sleep paralysis: A systematic review. Sleep Medicine Reviews, 15(5), 311-315.
- Schredl, M. (2018). Researching Dreams: The Fundamentals. Palgrave Macmillan.
Dreamer is a tool for reflection, not medical or psychological care. If dreams keep you from sleeping or living well, talk to a doctor or a therapist.
