Nightmares: causes, symptoms, and how to stop them

You’re being chased by a monster or facing some indescribable evil presence. Or maybe you’re just falling, falling, falling. Perhaps a loved one is being attacked. Whatever, you’re paralyzed, unable to run or help. These are just some of the many themes that haunt our dreams and literally keep some people up at night. 

What the heck is going on inside our heads? 

In most cases, the brain is trying to process everyday stresses, frustrations, or fears. But for some people, nightmares can result from a serious mental condition or certain medications.

"Nightmares are not a disease in themselves but can be a problem for the individual who anticipates them or who is greatly distressed by their nightmares,” says Antonio Zadra, Ph.D., a psychologist who studies sleep disorders at the University of Montreal. “People who have frequent nightmares may fear falling asleep—and being plunged into their worst dreams. Some nightmares are repeated every night. People who are awakened by their nightmares cannot get back to sleep, which creates artificial insomnia." 

The experts say that occasional nightmares are nothing to worry about, and there are some simple prevention strategies for avoiding those haunting dreams. For people who suffer more frequently, talk therapy or medication can help stop nightmares.

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Nightmares are, in a nutshell, very bad dreams, and they are pretty common. About half of children say they’ve had at least one, and around 85 percent of adults have at least one a year. Some people experience frequent nightmares that cause emotional, social, and work problems, and in such cases, a person might be diagnosed with a treatable mental disorder. But the occasional bad dream is not a cause for concern (Zak, 2021). 

• Somewhere between 4 and 10 percent of people have nightmares at least weekly (Levin, 2007).

• Women report more nightmares than men, but that gender difference doesn’t exist in children or older adults (Schredl, 2011).

• According to a Korean study, people over age 70 have more nightmares than people in their 50s (Park, 2021).

Dreams, broadly, are described as “a physiologically and psychologically conscious state that occurs during sleep” and which can include rich, realistic-seeming imagery, intense emotions, a sense of movement, and sudden changes in plot and characters (American Psychological Association, n.d.). Nightmares can do all that and add frightening elements that lead to sudden awakening (American Psychological Association, n.d.)

A short definition of nightmares is included in both the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and the International Classification of Sleep Disorders (ICSD-3) (Schredl, 2018):

“Repeated occurrences of extended, extremely dysphoric [uneasy or unhappy], and well-remembered dreams that usually involve threats to survival, security, or physical integrity.”

Let’s put some adjectives to this. According to one study, nightmares can make you feel “terrified, horrified, frightened, scared, panicky” or “furious, angry, irritated, outraged” or “depressed, lonely, hopeless, heartbroken” or “puzzled, perplexed, bewildered” or even full of remorse or regret (Robert, 2014).

Scientists also distinguish between true nightmares, which tend to be bizarre and involve some physical aggression, and less frightening “bad dreams,” typically rooted in interpersonal conflict and are less emotionally intense (Robert, 2014).

Exactly why we dream at all is a mystery, but it’s thought to help us process emotions. Like any dream, nightmares occur primarily during REM sleep, a phase of rapid-eye-movement that occurs toward the end of a sleep cycle, before waking (Fariba, 2021).

Humans go through a repeated cycle of deep sleep, lighter sleep, and wakefulness during a normal night of sleep. During most of the cycle, the brain’s relay center for incoming senses, called the thalamus, shuts off, letting you tune the world out. But during REM sleep, the thalamus activates, sending images and other sensations to the cerebral cortex, the part of the brain that processes information and turns it into memories. If all goes well, during REM sleep, your muscles are largely paralyzed—preventing you from acting out your nightmares  (National Institutes of Health, 2019). 

Stress, anxiety, fatigue, and irregular sleep are thought to be common causes of nightmares. (American Academy of Sleep Medicine, 2020). 

These presumed triggers are part of the continuity hypothesis of dreaming, which suggests our dreams and nightmares reflect what we’re worried about. There is a lot of firm evidence to support the hypothesis. Still, it’s unknown to what extent our daytime concerns are actually depicted in our nighttime imaginings, nor how literal or metaphorical these associations might be (Robert, 2014).

People frustrated because their basic psychological needs are not met—things like feeling competent and autonomous—are more likely to have recurring bad dreams in which they were falling, failing, or being attacked. That might reflect the psyche’s ongoing attempt to process the frustration through dreams, researchers suggested (Weinstein, 2018).

Several mental disorders are also thought to generate nightmares, including depression, schizophrenia, panic disorders, and borderline personality disorder. Post-traumatic stress disorder (PTSD) can be the source of nightmares both during and outside the REM period, leading to serious sleep disruption and insomnia (Zac, 2021). Some medications are also associated with nightmares, in some cases while using them and others when withdrawing from them (Zac, 2021).

The same underlying causes can also fuel nightmares in children, typically starting between age three and six and decreasing after age ten. Kids’ nightmares are likely to revolve around fears you might expect from a child: seeing monsters or being separated from their parents (Simard, 2008).

Parents take note: If a child has nightmares frequently or over a long period of time, and you can’t find an explanation, one possibility is that they’re being bullied (Wolke, 2014).

Studies on nightmare topics are mostly small, and often yield considerably different lists for the most common themes. If you have nightmares, though, you’ll likely recognize some of those that are most often reported, listed here in no particular order (Schredl, 2018):

• Falling

• Being chased

• Experiencing the death of someone close to you

• And the kicker to them all: being paralyzed

When someone is chased in a nightmare, they aren’t always able to remember or articulate what or who was chasing them, but when they can, it’s most often either an animal or some other unspecified creature or thing. The next most common aggressor is a human male (very rarely a female). Lower on the list: devils, ghosts, and, of course, monsters (Schredl, 2018).

Studies have found that men’s nightmares are more likely to involve falling. For women, death, injury, and health concerns predominate. Other themes include failure, health concerns, witnessing horror or physical aggression or violence, and accidents or natural disasters. Failure and helplessness are common themes for older people (Schredl, 2018). 

Here are examples of nightmares people have described (Robert, 2014):

• “The man rushed toward me with a knife, and I woke up.”

• “Looking up at the sky I see a missile coming right down at us.”

• “I suddenly realize that if I am floating in the air, it's because I am dead.”

Nightmares can be fueled by constant, underlying stress or be specific news or events, from terrorist attacks to natural disasters. During the early months of the COVID-19 pandemic, for example, people most affected by the pandemic reported increased dream recall and more negative themes, including these examples (Schredl, 2020):

• “I had a dream that they were probing everyone to see if they had the disease and if [the] probe went off you were infected and we were sent away to be killed.”

• “My dreams include my husband and work friends and grandchildren — trapped in boxes that are getting smaller. It is panic and claustrophobic.”

• “In a crowded area where some people were not wearing masks and observing social distancing.”

Then there are those awful dreams about having rotten, hole-ridden teeth or teeth falling out. In studies, these are most commonly referred to as bad dreams, not nightmares.

The bad teeth dreams don’t fit neatly with the continuity hypothesis of dreaming since most of us likely don’t spend our days worrying about our teeth falling out.

One study found evidence that people having this dream had experienced some clenching of their jaws while they slept, rather than the dream resulting from some deep psychological issues. However, the findings showed modest levels of correlation, not causation, and daytime stress and anxiety may still play a role in bad teeth dreams. So it’s not clear if the study has teeth, and the researchers themselves say the results should be interpreted with caution (Rozen, 2018).

If your nightmares become frequent or recurring and negatively affect your sleep or daytime life, you may have a diagnosable condition called nightmare disorder.

Around 4% of adults have a  nightmare disorder, either on its own or along with PTSD. It’s marked by recurring dreams that are extremely negative—those sorts that threaten your survival or security. You may struggle to get back to sleep after an episode, and the disorder causes distress that affects work, social interactions, and other normal function, with at least one of the following symptoms (Morgenthaler, 2018):

• Mood disturbance such as anxiety

• Fear of going to sleep

• Impaired concentration or memory

• Daytime sleepiness or fatigue

A person with nightmare disorder will typically wake from a nightmare very alert and remember the dream well. That’s different from “night terrors,” which can cause a person to kick or scream. One wakes groggily from night terrors and usually struggles to remember what they were about. Another condition that gets confused with nightmare disorder is REM sleep behavior disorder. This rare sleep disorder causes people to act out their dreams, including punching, kicking their bed partner, and jumping out of bed (American Academy of Sleep Medicine, 2020).

Nightmare disorder and other severe cases of recurring dreams are sometimes treated with imagery rehearsal therapy (IRT). A trained therapist has a person remember and write down their dream in this type of cognitive-behavioral therapy, then rewrite a more favorable version with a better ending. The person rehearses the new script to have it replace the original nightmare when dreaming does occur (Zac, 2021). 

IRT is the preferred approach compared with medication, as determined by the American Academy of Sleep Medicine (Morgenthaler, 2018).

When psychotherapies like IRT don’t work or aren’t available, a drug called prazosin might be prescribed for a nightmare disorder. A review of studies on both IRT and prazosin found no significant differences in the effectiveness of one over the other. Prazosin was found to decrease nightmare frequency and improve sleep quality (Yücel, 2019)

For the majority of people, nightmares don’t require formal therapies or drugs. Even if you meet the criteria for nightmare disorder, the symptoms might go away on their own (Zac, 2021). If you have the symptoms of nightmare disorder, you can consult a clinical expert for a possible diagnosis (Morgenthaler, 2018).

Otherwise, avoiding nightmares boils down to taking care of your physical and mental health and reducing stress in your life (MedlinePlus, 2020):

• Exercise regularly to promote better sleep.

• Set a sleep schedule, going to bed and waking up at the same time every day.

• Try relaxation techniques like yoga, meditation or simply listening to music.

• Avoid alcohol and caffeine.

If your child has nightmares, talk with them about their fears, don’t make fun of them, and reassure them about their safety (Moturi, 2010). It’s also OK to use a dim nightlight, and of course let the kid sleep with a special blanket or their favorite stuffed animal (American Academy of Sleep Medicine, 2020).

Here’s a neat trick you might try: Some people—a small percentage of the population—are sometimes aware of the fact that they are dreaming, a phenomenon called lucid dreaming. A handful of people have reported being aware of a nightmare and altering its course or deliberately waking themselves up to get out of it (Schredl, 2018).

Another potentially helpful tactic, according to dream researcher Deirdre Barrett, Ph.D., an assistant professor of psychology at Harvard Medical School: Set your alarm so that you don’t sleep in. That can force you to wake up at an unnatural moment, preventing the night’s final REM cycle from plunging you into another nightmarish scenario.

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Current version

June 23, 2021

Written by

Robert Roy Britt

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.