Nightmares are lengthy, elaborate dreams with imagery that evokes fear, anxiety, or sadness. The dreamer may wake up to avoid the perceived danger. Nightmares can be remembered upon awakening and may lead to difficulties returning to sleep or even cause daytime distress. Isolated nightmares are normal, but when dreams that bring extreme terror or anxiety recur often they can become a debilitating sleep disorder.


Occurring during rapid eye movement (REM) sleep, a nightmare is a dream that results in feelings of extreme fear, horror, distress, or anxiety. This phenomenon tends to occur in the latter part of the night and often awakens the sleeper, who is likely to recall the content of the dream.

Most nightmares are a normal reaction to stress, and some clinicians believe they help people work through traumatic events. Frequent occurrence of nightmares, however, becomes a disorder when it impairs social, occupational, and other important areas of functioning. At this point, it may be referred to as Nightmare Disorder (formerly Dream Anxiety Disorder) or "repeated nightmares," which is a term defined more specifically as a series of nightmares with a recurring theme.

Nightmares, which tend to be more common in girls than boys, usually begin in childhood before age 10 and are considered normal unless they significantly interfere with sleep, development, or psychosocial development. They may continue into adulthood where they are often associated with outside stressors, anxiety, or trauma. They may also exist alongside another mental disorder.

A closer look at dreaming might help in understanding nightmares.

Dreaming and REM Sleep

We typically spend more than two hours each night dreaming, yet scientists do not know much about how or why we dream. Sigmund Freud believed dreaming was a safety valve for unconscious desires. Only after 1953, when researchers first described REM in sleeping infants, did scientists begin studying sleep and dreaming carefully. They soon discovered that the strange, illogical experiences we call dreams almost always occur during the REM part of sleep. While most mammals and birds show signs of REM sleep, reptiles and other cold-blooded animals do not.

REM sleep begins with signals from the pons, an area at the base of the brain. These signals travel to a region called the thalamus, which relays them to the cerebral cortex—the outer layer of the brain responsible for learning, thinking, and organizing information. The pons sends signals that shut off neurons in the spinal cord, causing temporary paralysis of limb muscles. If something interferes with this paralysis, people will begin to physically act out their dreams—a rare, dangerous problem called REM sleep behavior disorder. For example, a person dreaming about a baseball game may run into furniture or inadvertently strike a person sleeping nearby while trying to catch a ball in the dream.

REM sleep stimulates the brain regions used in learning, which may be important for normal brain development during infancy. This would explain why infants spend much more time in REM sleep than adults. Like deep sleep, REM sleep is associated with increased production of proteins. One study determined that REM sleep affects learning certain mental skills. People taught a skill and then deprived of non-REM sleep were able to recall, upon awakening, what they had learned, while people deprived of REM sleep were not.

Some scientists believe dreams are the cortex's attempt to find meaning in the random signals received during REM sleep.  One theory suggests that, in trying to organize and interpret these signals, the cortex creates a "story" out of fragmented brain activity.


Criteria for a diagnosis of Nightmare Disorder

  • Repeatedly waking up with detailed recollection of long, frightening dreams that center around threats to survival, security, or physical integrity and usually occur in the second half of the sleep or nap period
  • Being oriented and alert instantly upon awakening
  • Experiencing distress or impairment of occupational, social, or other important areas of functioning
  • Having no general medical condition and using no medications or other substances that would cause these symptoms

Nightmares tend to be more common among children and adolescents and become less frequent toward adulthood. Nevertheless, about 50 percent of adults experience occasional nightmares, women more often than men, but do not require treatment. Adverse events, trauma, sleep deprivation, an irregular sleeping schedule, and jet lag may cause an increase in nightmares. The approximately 1 percent of adults who experience frequent nightmares should seek help if this leads to sleep avoidance or affects their work or social functioning.


• Anxiety or stress—in 60 percent of cases, a major life event precedes the onset of nightmares • Illness with a fever • Death of a loved one (bereavement) • Adverse reaction to or side effect of a drug • Recent withdrawal from a drug, such as sleeping pills • Excessive alcohol consumption • Abrupt alcohol withdrawal  • Breathing disorder during sleep (sleep apnea) • Sleep disorders (narcolepsy, sleep terror disorder) • Eating just before going to bed, which raises the body's metabolism and brain activity


If you are currently under stress, you may want to find a means of support from friends and relatives.

If you have experienced or witnessed trauma that is affecting you in other areas of functioning, you should consult a mental health professional.Talking about what is on your mind can go a long way toward helping you cope with past or current events. It is also recommended that you pay attention to your physical health, follow a regular fitness routine, and maintain consistency in your sleep habits. Exercise can help you fall asleep faster, have a deeper sleep, and wake up feeling more refreshed. Learning techniques to reduce muscle tension (relaxation therapy) can also help lessen anxiety.

If your nightmares started shortly after beginning a new medication, contact your health-care provider. He or she will advise you on discontinuing that medication if necessary and recommend an alternative.

Avoid using tranquilizers and alcohol to aid in sleeping and do not take caffeine or other stimulants prior to bedtime.

For nightmares resulting from the effects of "street drugs" or persistent alcohol use, seek counsel on reducing or discontinuing usage. Support groups such as Alcoholics Anonymous, have regularly scheduled meetings that might help you stay sober.

Call your health-care provider if nightmares occur more often than weekly, or if they prevent you from getting a good night's rest and persist for a prolonged period. Your medical history will be obtained and a physical examination performed.

Medical history questions documenting nightmares in detail may include:

  • Time Pattern of Nightmares    Do the nightmares occur repeatedly (recurrent)?    Do they occur in the second half of the night?
  • Quality of Sleep    Is there a sudden full awakening from sleep?
  • Other Issues    Does the nightmare cause intense fear and anxiety?     Do you remember a frightening dream (one with vivid imagery and storylike plot)?
  • Aggravating Factors    Have you had a recent illness?    Did you have a fever?     Were you in a stressful situation recently?
  • Other    Do you use alcohol? How much?     What medications do you take?    Do you use "street drugs"? If so, which ones?     Do you take natural supplements or alternative medicine remedies?     What other symptoms do you have?

Physical examination may include physical, neurological, and psychological assessments. Physical tests that may be done include blood tests (such as CBC or blood differential), liver function tests, thyroid function tests, and an EEG.

If treatment options addressing stress and anxiety, and the side effects of medication and substance use, do not resolve the problem, your health-care provider may send you to a sleep specialist who will perform a sleep study (polysomnography). In extremely rare cases, a patient will need to take special medications that suppress or reduce REM sleep, thus preventing nightmares.

After an examination by your health-care provider, you may want to add a diagnosis related to recurrent nightmares to your personal medical record.

Tips for a Good Night's Sleep From the National Sleep Foundation:

Set a schedule.

Go to bed at a set time each night and get up at the same time each morning. Disrupting this schedule may lead to insomnia. Sleeping in on weekends makes it harder to wake up early on Monday morning as it resets your sleep cycles for a later awakening.


Aim to exercise 20 to 30 minutes a day. Daily exercise often helps people sleep, although a workout before bedtime may have an adverse effect. For maximum benefit, work out about five to six hours before going to bed.

Avoid caffeine, nicotine, and alcohol.

Avoid drinks that contain caffeine, a stimulant. Sources of caffeine include coffee, chocolate, diet drugs, soft drinks, non-herbal teas, and some pain relievers. Smokers tend to sleep very lightly and often wake up in the early morning due to nicotine withdrawal. Alcohol robs people of deep sleep and REM sleep, so drinkers also sleep only lightly.

Relax before bed.

A warm bath, reading, or another soothing routine can make it easier to fall sleep. You can train yourself to associate certain restful activities with sleep and make them part of your bedtime ritual.

Sleep until sunlight.

If possible, wake up with the sun, or use very bright lights in the morning. Sunlight helps the body's internal clock reset itself daily. Sleep experts recommend exposure to an hour of morning sunlight for people having sleep issues.

Don't lie in bed awake.

If you can't fall asleep, don't just lie in bed. Do something else, like reading or listening to music, until you feel tired. The anxiety of being unable to fall asleep can actually contribute to insomnia.

Control the room temperature.

Maintain a comfortable temperature in the bedroom. Extreme heat or cold may disrupt sleep or prevent you from falling asleep.

See a doctor if your sleeping problem continues.

If you have trouble falling asleep every night, or if you always feel tired the next day, then you may have a sleep disorder and should see a physician. Your primary care physician may be able to help you, or you can consult a sleep specialist at a major hospital near you. Most sleep disorders can be treated effectively.

Researchers now know that sleep is an active and dynamic state that strongly influences our waking hours. Innovative techniques, such as brain imaging, help researchers understand how different brain regions function during sleep and how activities and disorders affect sleep.

In fact, scientists have had some success in controlling dreams. In one experiment, subjects were trained to play the computer game, Tetris, which involves the manipulation of pieces of a falling wall. The scientists monitored the participants' dreams over the first two nights, and more than half of the subjects reported dreaming of falling Tetris pieces. This type of research will likely contribute to developing treatments for nightmares.


  • American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders
  • National Institutes of Health, National Library of Medicine
  • National Institute of Neurological Disorders and Stroke

Last reviewed 01/10/2019