Nightmares: why they happen & what helps
Bad dreams can shake you for hours, but they are common, they make sense, and there are proven ways to make them softer and rarer.
By the numbers
How common nightmares are, and who has them most.
Adults
Trauma & mood
Children
What is a nightmare?
A vivid, frightening dream that wakes you up.
A nightmare is a vivid, realistic and upsetting dream that wakes you up. They often involve a threat to your safety or survival. You usually remember them clearly.
Most nightmares happen in the second half of the night, during REM sleep. That is the stage when most dreaming happens, and you get more of it towards morning.
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In a large Finnish study, just under half of adults had at least one nightmare in the past month. Bad dreams now and then are part of being human.
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For some people nightmares come weekly or even nightly. Nightmare disorder is when repeated nightmares cause distress or make daily life harder. It affects about 4% of adults.
Frequent nightmares have been linked with exhaustion, headaches, low life satisfaction and finding it harder to work.
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How they differ
- Night terror: screaming or thrashing while still asleep, early in the night, and usually not remembered
- Nightmare: a scary dream that wakes you fully, later in the night, and is remembered
- Sleep paralysis: being awake but unable to move for a short time while falling asleep or waking
Why nightmares happen
Common triggers, and what researchers think is going on.
No one knows the exact cause. One idea is that being on edge, irritable or on guard during the day carries over into sleep. Another is that the brain struggles to “switch off” fear memories at night.
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Stress, anxiety and worry are common triggers. People who react strongly to stress, or find their feelings hard to settle, may be more prone to nightmares.
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Being very tired or unwell can trigger nightmares. Very short or very long sleep has also been linked with them.
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Seeing something frightening, like a scary film, can set off nightmares. A severe injury can also disturb sleep for 4 to 6 weeks afterwards.
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Nicotine can cause nightmares, and so can cutting back on alcohol after heavy drinking. Some prescribed treatments can also cause vivid or frightening dreams.
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Nightmares are more likely alongside other sleep conditions, such as sleep apnea, restless legs syndrome, narcolepsy and periodic limb movements.
Nightmares after trauma
When the night replays what happened.
Nightmares are one of the most common ways trauma shows up. Up to 80% of people with PTSD report them, and they often replay the event or its feelings.
Exposure to war raises nightmare rates even decades later. A Finnish study found that people with war experiences still had more frequent nightmares, insomnia, low mood and anxiety.
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Fear of nightmares can lead people to put off going to sleep. Feeling on alert makes restful sleep hard, and pushing memories away in the day can make them louder at night.
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If dreams cause kicking and screaming, bed partners can be affected. Talking about it together in the daytime can ease worry and embarrassment.
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Sleep experts recommend imagery rehearsal therapy for nightmares linked to PTSD. CBT, CBT for insomnia, EMDR and exposure, relaxation and rescripting therapy may also be used.
The National Center for PTSD says CBT for insomnia reduces how many nightmares people have and how upsetting they are.
Nightmares, mood & poor sleep
How nightmares, low mood and insomnia feed each other.
In a study of nearly 14,000 adults, insomnia, exhaustion and a negative view of yourself were the strongest links to frequent nightmares. The study could not show which came first.
Nightmares are also around three times as common in people with generalized or social anxiety. They are linked with depression too.
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How it can go
- A nightmare wakes you and it’s hard to get back to sleep.
- You feel drained and low the next day.
- You start to dread bedtime.
- Worry and short sleep make another nightmare more likely.
Insomnia and low mood both make frequent nightmares more likely, and nightmares in turn disturb sleep.
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In Finland, adults with symptoms of seasonal low mood had higher odds of frequent nightmares and insomnia.
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Untreated long-term nightmares have been linked with a higher risk of suicide attempts. That’s one reason recurring nightmares deserve care.
What to do right after a nightmare
Settle your body, then ease back towards sleep.
Waking from a nightmare can leave your heart pounding. The goal is to remind your body it’s safe now. These simple steps can help.
Try this
- Turn on a soft, low light.
- Feel your feet on the floor or the weight of the blanket.
- Name 5 things you can see in the room.
- Breathe out slowly, a little longer than you breathe in.
- Say to yourself: “That was a dream. I’m here, and I’m safe now.”
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Lying awake in fear can link your bed with worry. Many people find it helps to get up, do something quiet and dull in low light, then return when sleepy.
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Keeping a log of your sleep and how often and how strong your nightmares are is part of nightmare treatment. It can show patterns and triggers.
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Ideas
- A calm, relaxing routine before bed
- Keeping a regular sleep schedule
- Less alcohol and nicotine, especially in the evening
- Something soothing to watch or read late at night instead of scary content
- Time to name and put down the day’s worries earlier in the evening
Imagery rehearsal: rewriting the dream
The therapy sleep experts recommend most.
The main U.S. sleep experts’ group (AASM) recommends imagery rehearsal therapy for both nightmare disorder and nightmares linked to PTSD. It is the only nightmare treatment they rated as “recommended”.
The idea is simple. While awake, you change a recurring nightmare so it’s less frightening, then rehearse the new version every day. Daily practice is an important part of it.
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- Learn about what nightmares are and why they keep coming back.
- Pick one recurring nightmare. Start with a milder one, not the worst.
- Write a short outline without lots of detail.
- Change the story in any way you like, so it feels safer or calmer.
- Picture the new version for a few minutes each day while awake.
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You might
- Add a helper, friend or protector
- Change the place to somewhere you feel calm
- Give yourself a new ability, like flying or a shield
- Make the threat shrink, turn silly or walk away
- Stop the scene and step out of it
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Pooled studies show imagery rehearsal and a related therapy can bring moderate to large drops in how often nightmares happen, and smaller gains in sleep.
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A therapist can guide imagery rehearsal and help if it stirs up strong feelings. This matters most when nightmares come from trauma.
Other therapies that can help
More talking-therapy options, A to Z.
Sleep experts say several other approaches “may be used” for nightmares. The evidence for these is less clear than for imagery rehearsal, but they help some people.
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Cognitive behavioral therapy may be used for nightmare disorder and for nightmares linked to PTSD. The NHS says CBT can help children and adults with frequent nightmares.
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CBT-I may be used for nightmares linked to PTSD. The National Center for PTSD says it reduces nightmares and the distress they cause.
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Eye movement desensitization and reprocessing may be used for nightmares linked to PTSD.
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ERRT is a CBT-based therapy related to imagery rehearsal. It may be used for both nightmare disorder and trauma nightmares.
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Lucid dreaming therapy may be used for nightmare disorder. The idea is to learn to realise you are dreaming, which can give a sense of control.
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Progressive deep muscle relaxation and systematic desensitization may be used for nightmare disorder. Both teach your body to stay calmer around frightening images.
Children and adults: what’s different
Nightmares change with age. So does what helps.
Nightmares can start as young as 6 months and tend to peak between ages 3 and 12. Most children grow out of frequent nightmares.
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Go to your child quickly, let them know you are there, and let them tell you about the dream if they want to. Remind them dreams aren’t real.
Check for things that might be frightening them, like shadows, and leave a light on if it helps.
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Stress and worry are common triggers at any age. CBT can help children with frequent nightmares.
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In adults, nightmares are often tied to stress, trauma, insomnia or low mood. In men they became more common with age, while in women they stayed steady.
Imagery rehearsal therapy is the recommended treatment for adults.
See a provider for a child if they
- Have frequent nightmares
- Have nightmares after an upsetting or frightening event
- Still have nightmares after age 6
How to support someone
For partners, parents, roommates and friends.
Watching someone you love wake up frightened can feel helpless. You can’t stop the dreams, but you can make the night feel safer.
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- Ask before touching: some people need space after a trauma nightmare
- Offer water and a soft light
- Remind them where they are and that they’re safe
- Speak slowly and quietly
- Stay until they feel settled, if they want you to
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- Ask what helps them, and what doesn’t
- Encourage support if nightmares are frequent
- Don’t make them retell a dream they don’t want to share
- Help protect a calm evening routine
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Veterans groups, trauma support groups and faith communities can help people feel less alone. Hearing that others have nightmares too can lift a lot of shame.
When and where to get help
Signs it’s time to talk to someone, and who to call.
Talk with a clinical provider or therapist if
- An adult has regular nightmares that affect sleep or daily life
- Nightmares started after a traumatic event
- You avoid going to bed because of them
- You also snore loudly, stop breathing at night or feel very sleepy in the day
- You think something you take may be causing them
A primary care provider can check for other causes and refer you. Therapists trained in CBT, CBT-I or trauma therapies, and sleep specialists, can offer imagery rehearsal and related treatments.
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Sources
- American Academy of Sleep Medicine (AASM); Morgenthaler T.I. et al. (2018). Position Paper for the Treatment of Nightmare Disorder in Adults (Journal of Clinical Sleep Medicine)
- American Academy of Sleep Medicine (AASM) (2015). Depression and insomnia are strongest risk factors for frequent nightmares
- Sandman N. et al., peer-reviewed study (2015). Nightmares: Risk Factors Among the Finnish General Adult Population (Sleep)
- Sandman N. et al., peer-reviewed study (2013). Nightmares: Prevalence among the Finnish General Adult Population and War Veterans during 1972–2007 (Sleep)
- Sandman N. et al., peer-reviewed study (2016). Winter is coming: nightmares and sleep problems during seasonal affective disorder (Journal of Sleep Research)
- Cleveland Clinic. Nightmare Disorder
- NHS (UK National Health Service). Night terrors and nightmares
- National Heart, Lung, and Blood Institute (NHLBI), NIH. How Sleep Works: Sleep Phases and Stages
- National Center for PTSD, U.S. Department of Veterans Affairs. Sleep Problems and PTSD
- American Academy of Pediatrics (AAP), HealthyChildren.org. Nightmares, Night Terrors & Sleepwalking in Children: How Parents Can Help
- Spangler P.T., Sim W., peer-reviewed review (2023). Working with dreams and nightmares: A review of the research evidence (Psychotherapy)
This guide is for education and self-care. It is not a diagnosis or a substitute for professional care. Please talk to a counselor or clinical provider about your health. Reviewed October 2026.

