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May 22, 2024/Living Healthy/Sleep

7 Reasons You’re Having Nightmares

Stress, alcohol, sleep apnea and (you guessed it!) scary movies are a few common causes of bad dreams

Person in bed experiencing nightmares

You’re falling from a great height. You’re being chased by a menacing monster. You’re giving a big presentation in front of the entire school and when you look down, you realize that you’re standing stark naked in front of everyone you know.


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Whatever the plot of your personal horror film, there’s no feeling quite as scary as waking up sweaty, shaking and filled with a sense of dread … and then realizing that it was all a dream. Or, more accurately, it was all a terrible nightmare.

But why? And perhaps more importantly, what you can do to stop having nightmares?!

Sleep psychologist Alaina Tiani, PhD, tells us why nightmares happen and shares tips that can help you stop living out the lyrics to Metallica’s iconic “Enter, Sandman” so you can start getting a more peaceful night’s sleep.

Is it normal to have nightmares?

Nightmares are no fun, but they can, at least, be normal. An estimated 85% of adults report having occasional nightmares, and nightmares in children are especially common.

“In general, bedtime is a common time for our minds to start having worrisome thoughts,” Dr. Tiani says. “It’s quiet, it’s dark and there’s not a whole lot of distraction going on.”

But when nightmares start to become frequent or so upsetting that they impact your sleep, they can begin to take a toll on your waking hours, too.

How’s this for scary? Studies show that 1 in 20 people experience a nightmare at least once a week, and some people have them even more often. In the U.S., 2% to 8% of people experience nightmare disorder, a condition categorized by nightmares so vivid and distressing that they affect their quality of life.

“It’s common to have more nightmares than usual when you’re going through a stressful time,” Dr. Tiani notes, “but typically, they’ll resolve on their own once the stressor resolves.”

If your nightmares continue for weeks or even months, it’s time to bring it up with a healthcare provider.

What causes nightmares?

“Most people have a random nightmare here or there, and you may be more susceptible to them after dealing with stress or watching a scary movie,” Dr. Tiani points out. “But there are other causes, too.”

You can have nightmares for all kinds of reasons, including anxiety, sleep deprivation, drug and alcohol use, and medical conditions like obstructive sleep apnea and post-traumatic stress disorder (PTSD). Nightmares can also be a side effect of certain medications.

But why? That part is less clear.

Scientists still don’t know exactly why we dream — or why we dream about the things we do, nightmares included. Though that’s not a particularly satisfying answer, it’s true: Our brains are complex places, and neuroscientists are always studying exactly what happens in there.

“One hypothesis is that our brains are trying to play out or otherwise deal with unresolved feelings that are causing us stress and anxiety during the daytime,” Dr. Tiani shares. “Oftentimes, those feelings may be fodder for our nightmares.”


Research shows that nightmares are most likely to occur during rapid eye movement (REM) sleep, which usually happens during the second half of the night. REM sleep, which makes up about 25% of your total time asleep, is the stage of sleep where most of your dreams happen, in general.

Can horror movies cause nightmares?

There’s a good reason you weren’t allowed to watch slasher flicks before bed as a kid: They can indeed cause nightmares! In fact, anything that causes you stress or anxiety can ultimately bring on bad dreams, so you may want to think twice before you crack open that murder novel or binge a true-crime podcast.

“You might find yourself walking more carefully through your home at night or checking behind doors,” Dr. Tiani says. “But watching scary movies isn’t the only thing that can activate your nervous system in that way.”

Engaging in other behaviors close to bedtime can cause similar feelings, like:

Life stress

If you’re going through a tough time during your waking hours, be it a big move, a new job, a tough breakup or the loss of a loved one, it could impact the way your brain operates come nighttime.

“Unresolved problems that we experience during the day can cross over into nightmare activity,” Dr. Tiani says.

Post-traumatic stress disorder

Nightmares are one of the stress responses associated with post-traumatic stress disorder (PTSD), a mental health disorder that can develop after a traumatic event that threatens your life or your sense of safety. An estimated 70% to 90% of people with PTSD experience nightmares.

“These nightmares are often recurrent, frequent and very vivid or disturbing,” Dr. Tiani explains, “and they’re usually related to the traumatic experience that the individual has encountered.”

The main treatment for PTSD is talk therapy. A therapist can help you safely confront distressing memories and emotions, which can lessen symptoms like nightmares and flashbacks.

Alcohol and other substances

Drugs, alcohol and caffeine can all cause nightmares, as can withdrawal (the effects of quitting) from these substances.

  • Caffeine: There are a few reasons to switch to decaf as the day goes on, and nightmares may be one of them. “Some people report a correlation between having caffeine too close to bedtime and increased nightmare activity,” Dr. Tiani says.
  • Alcohol: Drinking alcohol close to bed can disrupt your REM sleep, causing what’s known as “REM rebound” — and REM rebound is associated with increased nightmares. “Alcohol is a depressant, so it tends to help you fall asleep,” Dr. Tiani acknowledges, “but it can also wreak havoc on your sleep throughout the night by causing disruptions and changes in your sleep architecture.”
  • Drugs: Stimulants like cocaine and methamphetamine may cause nightmares, especially during withdrawal.


Certain medications

Nightmares can be a side effect of some medications, like:

These aren’t the only medications that can cause nightmares, and not everyone who takes these medications will have nightmares. If you do start to have nightmares and suspect they’re related to a medication, talk to your healthcare provider. They may be able to adjust your dosage or switch you to a new medicine.

Sleep deprivation

When you don’t get enough sleep, your health takes a serious hit. Chronic sleep deprivation is associated with conditions from depression to heart attacks — and even a little bit of sleep deprivation can have a big impact on how you feel.

“We know that sleep deprivation and other sleep problems, like having an irregular sleep schedule, can be linked to a higher likelihood of having nightmares,” Dr. Tiani says.

Obstructive sleep apnea

Another common sleep disorder that’s been linked to nightmares is untreated obstructive sleep apnea.


“People with this condition essentially don’t get enough oxygen to their brain because of breathing disturbance during the night,” Dr. Tiani explains, “which has been strongly linked with nightmares.”

Nightmares related to obstructive sleep apnea can sometimes feature scary, breathing-related themes like strangulation, suffocation, choking and being trapped in small spaces, like in an elevator.

Can nightmares be avoided?

Just like death and taxes, nightmares are, to some extent, a fact of life. There’s no way to fully guarantee that you’ll never have one again. But if you’re able to identify a known cause (or two or three) of your nightmares, you can take steps to try to prevent them.

Dr. Tiani walks us through a few things we can do to try to rest easy and avoid falling asleep with bad dreams.

1. Manage your stress

Often easier said than done, we know. But how frazzled you feel during the day can inform the film that plays out in your mind overnight, so learning to cope with stress can go a long way toward keeping nightmares at bay.

“It’s important to develop the coping skills necessary to manage your day-to-day stressors,” Dr. Tiani says. “If you continue to experience the effects of chronic, unresolved stressors, those themes may start to pop up as distressing dreams.”

2. Be cautious about the content you consume

There are lots of reasons to limit screen time before bed, and here’s another: Anything you read, watch or listen to close to bedtime can worm its way into your brain and turn into nightmares.

“Be mindful of the media that you take in within the last few hours before bedtime, including the news you read and the videos you watch,” Dr. Tiani advises. “Anything stressful or overwhelming can heighten the risk of those themes or emotions presenting in your dreams.”

3. Take time to wind down before bed

Whether or not you’re worried about nightmares, everyone can benefit from good sleep hygiene, a term that refers to the healthy habits, behaviors and environmental factors you can take charge of to help you get a good night’s sleep.

“Many of us go through the day feeling stressed or overwhelmed, and we have so many things to do that we’re on the go right up until bedtime,” Dr. Tiani recognizes. “Then, we expect to hit the pillow and fall right asleep, which isn’t necessarily realistic.”

Instead, she suggests working on giving yourself time to wind down between your busy day and bedtime. An hour is ideal, but any designated quiet time is better than none at all. Use the time for quiet activities like reading, flossing and implementing a skin care routine — and be sure to turn off your screens.

“Think of it as a buffer zone between daytime and nighttime,” Dr. Tiani says. “Having a relaxing, calming wind-down routine promotes a more pleasant end to your day.”

4. Get enough high-quality sleep

The effects of sleep deprivation are real, and nightmares are just a small piece of the puzzle. Most healthy adults need seven to nine hours of sleep, though those needs vary with age, health and other individually specific factors.

If you have trouble getting enough sleep because of insomnia — whether because you can’t fall asleep or because you can’t stay asleep — your healthcare provider may want to run a sleep study to help get to the bottom of the issue.


5. Listen to something relaxing before bed

Want to point your mind in the right direction as you drift off to sleep? Give it an assist.

“There are ways to help your brain relax and be a little more mindful, which is always a positive thing,” Dr. Tiani says. “Guided meditation or imagery, for example, can be really helpful because it leads your brain in a more constructive direction.”

Guided imagery is a relaxation technique in which you listen to an audio recording of a narrator who talks you through a soothing meditation. But if this type of meditation doesn’t quite resonate with you, look into other styles of meditation and breathwork to find one that feels right. Doing just 10 minutes of it can help you crawl into bed more relaxed and at peace.

6. Keep a consistent sleep schedule

When you keep your sleep and wake times relatively consistent, you help train your internal clock (aka your circadian rhythm). This primes your body to know when it’s time to go to bed and when to wake up, which allows you to fall asleep faster, sleep better and wake up feeling more well-rested.

“Irregularity in your sleep schedule may not be the sole cause of nightmares, but it certainly can play a role,” Dr. Tiani says. “It’s good to do anything you can to support good sleep health, which will also support the reduction of nightmares.”

What to do if you have frequent nightmares

If nightmares are impacting your quality of life, it’s time to talk to a healthcare provider who can help. They can help get to the bottom of what’s causing your nightmares and develop a treatment plan.

“You may fit the criteria for nightmare disorder if you’re having nightmares frequently, if they’re recurrent or if they’re causing some type of problem for you, whether that’s sleep disturbance or daytime problems, like distress from the nightmares,” Dr. Tiani says.

If you’re diagnosed with nightmare disorder, your provider may recommend something called imagery rehearsal therapy (IRT), a type of therapy that examines the common themes of your nightmares.

“It involves figuring out all of the details of those dreams, in terms of elements like sights, sounds and smells,” Dr. Tiani explains. “We ask people to write out all of that, and then, we work together to do something called ‘rescripting the dream narrative.’ This can help lessen the distress that nightmares cause and can decrease their severity and frequency.”

Everyone has a bad dream every now and then. But if your nightmares are getting in the way of your ability to enjoy your life, a healthcare provider can help get you on the right track. You deserve to rest easy.

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