The short answer
Dream interpretation is not prediction and not diagnosis. This article separates what sleep research observes from what popular interpretation associates with the theme.
A nightmare is a dream with fear, distress or anger strong enough to wake you up or leave you feeling shaken for a while. Having one now and then is normal. They tend to show up more during stressful periods, after difficult events, with irregular sleep and when starting or stopping certain substances.
When they happen almost every week and start disrupting your sleep or your day, they become a recognized condition with an effective treatment, explained below.
Read also: Dreams about falling and Sleep paralysis.
Why the brain creates scary scenes
Most vivid dreams happen during REM sleep, which is concentrated in the second half of the night. That is why so many nightmares wake people in the early morning hours.
A well-known hypothesis by Finnish researcher Antti Revonsuo suggests that dreaming about threats works as a rehearsal: the brain simulates danger in a safe setting. It is debated, not a consensus, but it helps explain why so many dreams revolve around escape and attack.
Source: Revonsuo, The reinterpretation of dreams, Behavioral and Brain Sciences, 2000.
The most common nightmares
An online study of more than a thousand recent nightmares found recurring themes: being chased, physical aggression, the death or injury of loved ones, falling, and being late or failing at something important.
| Nightmare theme | Read more |
|---|---|
| Being chased | dreams about being chased |
| Falling | dreams about falling |
| Someone dying | dreaming about death |
| Teeth falling out | teeth falling out dreams |
| Animal attacks | snake attacking and lion attacking |
| Fire and disasters | dreaming about fire |
Source: Schredl and Göritz, Nightmare Themes, Journal of Clinical Sleep Medicine, 2018.
What helps you have fewer nightmares
- A regular sleep schedule: sleep loss and shifting bedtimes can trigger a rebound of REM sleep.
- Less alcohol at night: it fragments sleep in the second half of the night.
- A buffer between the news and bed: tense content right before sleep often resurfaces.
- Writing the dream down: describing it after waking takes some of the emotional charge out of it.
- Medication check: if nightmares started after beginning or stopping a medication, talk to the prescriber rather than stopping on your own.
See also nighttime habits that help you sleep better.
When it needs treatment
If nightmares are frequent, make you afraid to fall asleep, leave you exhausted or started after a trauma, talk to a doctor or a therapist. The American Academy of Sleep Medicine recommends imagery rehearsal therapy: while awake, you rewrite the ending of the nightmare and rehearse the new version for a few minutes each day.
Waking up unable to move is something different, sleep paralysis, and it has an explanation too.
What about popular interpretation?
In popular belief, nightmares are often seen as warnings or omens. There is no scientific basis for that. What research does show is a link with what you live and feel while awake, known as the continuity hypothesis. To learn how to look at any dream, see what science and culture say about dream meanings.
Read also: nightmares that keep returning; the giant wave nightmare; the car accident nightmare; night terrors, which are different from nightmares.
Sources
- Revonsuo A. The reinterpretation of dreams: An evolutionary hypothesis of the function of dreaming. Behavioral and Brain Sciences, 2000. https://doi.org/10.1017/S0140525X00004015
- Schredl M, Göritz AS. Nightmare Themes: An Online Study of Most Recent Nightmares and Childhood Nightmares. Journal of Clinical Sleep Medicine, 2018. https://doi.org/10.5664/jcsm.7002
- Morgenthaler TI et al. Position Paper for the Treatment of Nightmare Disorder in Adults: An American Academy of Sleep Medicine Position Paper. Journal of Clinical Sleep Medicine, 2018. https://doi.org/10.5664/jcsm.7178
- Schredl M, Hofmann F. Continuity between waking activities and dream activities. Consciousness and Cognition, 2003. https://doi.org/10.1016/S1053-8100(02)00072-7
Frequently asked questions
Are nightmares normal?
Yes. Occasional nightmares are common. They deserve attention when they become frequent and disrupt your sleep or your day.
Why do I have more nightmares early in the morning?
Because REM sleep, when the most vivid dreams happen, is concentrated in the second half of the night.
Can nightmares be treated?
Yes. Imagery rehearsal therapy is recommended by the American Academy of Sleep Medicine for frequent nightmares.
Is a nightmare a warning sign?
There is no evidence for that. Nightmare themes tend to reflect worries and emotions from waking life.
