Most of us know how it feels to wake from a nightmare: the clammy palms. The racing heart. The frightening, life-like images. Though they aren’t real, nightmares can be terrifyingly vivid. For those of us who suffer from them frequently, they can even make us afraid to go to sleep.
A nightmare is a dream with a negative subject matter that invokes fear or other disturbing emotions. (1) A nightmare is distinguished from an ordinary bad dream by its tendency to wake a dreamer from sleep. Nightmares typically create a powerful emotional reaction, and may trigger fear, anger, sadness, guilt, or anxiety.
As rare as we might wish they were, nightmares are quite common. They occur on occasion in approximately 50% of adults around the world, and are even more prevalent in children and adolescents.
Note: The content on Sleepopolis is meant to be informative in nature, but it shouldn’t be taken as medical advice, and it shouldn’t take the place of medical advice and supervision from a trained professional. If you feel you may be suffering from any sleep disorder or medical condition, please see your healthcare provider immediately.
The Stuff of Nightmares
The word nightmare is derived from “mare,” variations of which appear in many ancient languages. Possible original meanings of mare may be to crush or oppress, to harm, or a sense of doom. The mare appears in Old German and Slavic folklore as a monstrous being that sits on the chest during sleep and causes bad dreams. The mare figure is particularly well-illustrated in Henry Fuseli’s 1781 painting, The Nightmare.
The Nightmare by Henry Fuseli, 1781, Detroit Institute of Arts
Nightmares tend to occur during the final stages of REM sleep, the phase of sleep when dreams are most vivid and brain activity most closely resembles wakefulness. Activation of the amygdala, a primitive structure in the brain designed to recognize and respond to potential threats, may explain some nightmares, particularly in those with chronic activation of the amygdala due to stress, trauma, or childhood adversity.
Changes in brain waves may also be responsible for some nightmares, or at least the ability of some dreamers to remember their disturbing dreams. (2) Nightmares are considered normal unless they interfere with daily life, disrupt sleep more than occasionally, or create persistent fear of falling asleep.
Common themes of nightmares include (3):
- Aggression or violence
- Physical jeopardy
- Being chased
Another frequent theme of nightmares include environmental calamity, such as an apocalypse or nuclear disaster. Falling, being trapped, drowning, or being unable to move are other common subjects of nightmares, which may have complex narratives and feel as real to the dreamer as waking life.
Signs and Symptoms of Nightmares
Symptoms of nightmares are typically obvious, due to the strong emotions associated with such dreams and the likelihood that the dreams will be remembered.
Typical signs and symptoms include:
- Experiencing dreams with disturbing or upsetting themes, such as death, threat to physical safety, war, or personal conflict
- Sitting upright in bed after a dream
- Waking feeling anxious
- Waking with an increased respiration rate
- Crying after a dream
- Waking from sleep screaming or shouting
Nightmares may make returning to sleep difficult, particularly if they cause physical symptoms such as increased heart rate, perspiring, or feelings of shakiness due to adrenaline release.
Causes of Nightmares
Ordinary nightmares may be triggered by such simple causes as a physically uncomfortable sleep position, headache, or fever. Eating before bed may elevate the rate of metabolism, thereby increasing brain activity and triggering nightmares. Nightmares that result from these types of causes are generally not chronic, and only occasionally disrupt sleep.
Other causes of nightmares, however, are more complex, and may persist for weeks, months, or longer. Children may experience both ordinary nightmares or night terrors, an arousal disorder that typically occurs in non-REM sleep.
Non-REM SleepIncludes three of the four stages of sleep, and is characterized by lack of eye movement, minimal dreaming, and various depths of sleep, from the light sleep of the N1 stage to the restorative, slow-wave sleep of the N3 stage.
Pregnancy and Hormonal Changes
Pregnancy and other hormonal changes can also trigger nightmares. (4) This may be due to sleep disruptions caused by hormonal fluctuations, or by the hormonal fluctuations themselves. Waking because of discomfort during pregnancy may impact REM sleep, the stage of sleep when dreams are most likely to occur.
Perimenopause and the usual menstrual cycle may cause nightmares due to changes in body temperature and progesterone. Such changes can interrupt sleep, which may prompt unusually vivid dreams and increase the chance that dreams will be remembered.
Post-Traumatic Stress Disorder
Nightmares are a common feature of post-traumatic stress disorder, and may be one of the most disturbing aspects of the disorder. (5) As many as 80% of people diagnosed with PTSD report experiencing regular nightmares.
PTSD is characterized by three clusters of symptoms: intrusion, avoidance, and hyperarousal. Post-traumatic nightmares are part of the intrusion cluster, which includes flashbacks, intrusive thoughts, and physiological distress, also referred to as body memory.
Though nightmares that occur after a traumatic event may be a direct replay of past experiences, they may also be quite different. Typically the emotions remain the same, even if the setting or narrative of the nightmare changes. Nightmares due to PTSD may occur every time a sufferer falls asleep, leading to disturbed sleep as well as feelings of panic and fear.
Nightmares that occur after trauma may be different from ordinary nightmares, not just in their frequency and intensity, but when they occur. Nightmares associated with PTSD are more likely to take place in sleep stages other than REM, occur earlier in the night, and to involve body movements or vocalization such as shouting or speaking. (6)
Depression and Other Mood Disorders
Anxiety and depression are two of the most common causes of nightmares. Depression sufferers are more likely to report nightmares, as well as generally negative content in their dreams. Distress from negative dreams may be particularly acute in those diagnosed with depression, anxiety, or other mood disorders. (7)
Some studies suggests that dream content may change when a person suffering from bipolar disorder changes from a manic to a depressive state or vice versa. (8)
People who experience both insomnia and nightmares may be particularly at risk for depression and other mood disorders. Just as depression and mood disorders such as schizophrena, bipolar disorder, and anxiety disorder may cause nightmares, nightmares may also worsen or contribute to mood disorders.
Pre-existing anxiety may be heightened by disturbing and vivid dreams, while nightmares that disturb sleep may worsen depression due to sleep deprivation and fear of falling asleep.
FAQQ: Can anti-depressants cause nightmares? A: Nightmares may be a side effect of certain antidepressants. While older tri-cyclic medications are less known for nightmares, newer SSRI's may cause nightmares due to their impact on REM sleep.
Withdrawal from medications, recreational drugs, and alcohol is a frequent cause of nightmares. (9) Withdrawal from barbiturates and benzodiazepines may cause what’s termed “REM sleep rebound,” a period of longer, more vivid dreams that can occur after chronic suppression of REM sleep. (10) REM rebound may also be caused by sleep deprivation.
Disruption to sleep architecture may also help explain why nightmares plague people in withdrawal. Drug, alcohol, and medication use can alter sleep cycles, depressing brain function and changing the length and quality of sleep stages. Once a substance is stopped, shifts between non-REM and REM sleep can become irregular, disturbing sleep and increasing the risk of nightmares.
Delirium tremens, also known as alcohol withdrawal syndrome, is caused by reductions in certain brain chemicals after consumption of alcohol is stopped. Alcohol withdrawal causes severe disruption to the brain and nervous system, and may be fatal, particularly if not treated in a hospital or an addiction facility.
One of the most common signs of the syndrome is nightmares, which may be vivid and unrelenting. As in the case of barbiturate withdrawal, the nightmares of alcohol withdrawal syndrome may result from REM sleep rebound.
Other signs include:
- Elevated blood pressure
- Increased heart rate
Nightmares and other effects of alcohol withdrawal syndrome may begin within two to three days after alcohol is stopped, and peak within five to seven days. Even after other symptoms of the syndrome subside, nightmares can persist for several days or weeks.
Common antidepressants such as SSRI’s are known to cause nightmares in addition to other effects on sleep. (11)
Antidepressants influence neurotransmitters such as dopamine, serotonin, and norepinephrine, which impact sleep as well as emotions. The result may be unusually vivid dreams and nightmares.
Though the effect may be temporary while the body adjusts to a particular medication, nightmares may persist, and for some users, continue as long as they take the drug.
Other medications may cause nightmares, as well. These include:
- Certain antibiotics
- Blood pressure medications
- Dopamine receptor agonists
Sedatives and hypnotics, some of which are prescribed for insomnia or other sleep difficulties, may increase the risk of disturbing dreams and nightmares once they are stopped due to their suppression of REM sleep. Sleep that is less sedated may also lead to better recollection of dreams, both normal and disturbing.
HypnoticsA class of psychoactive sleep medications that include Ambien, Halcion, Lunesta, and Sonata.
Nightmares are typically diagnosed by reporting of symptoms alone. A physical examination and/or overnight sleep study may be ordered if sleep is severely disturbed, or to rule out possible contributing factors such as sleep disorders or other medical conditions.
Sometimes a sleep study can be conducted at home, but often this type of diagnostic tool requires a polysomnography performed in a sleep study lab. A polysomnography involves the placement of sensors which monitor and record brain waves, blood oxygen levels, body movements, and heart and breathing rates. The test may be videotaped, as well.
Nightmares in Children
Nightmares occur frequently in children and adolescents, and considered normal unless they persist, cause fear during waking hours, or create chronic sleep disturbance. They may be more frequent in children who have recently experienced a change in life circumstances, death of a family member, or other stressor. (12)
Common causes of nightmares in children include:
- Stress and anxiety
- Family conflict
- Disruptions to routine
- Significant life events such as moving, birth of a sibling, or divorce
Unlike a typical nightmare, night terrors take place during non-REM sleep. They are considered a parasomnia, and are most commonly seen in children between the ages of two and four.
Night terrors may cause some or all of the following symptoms:
- Yelling or screaming in sleep
- Sitting upright in bed
- Moving or thrashing in bed
- Appearing agitated while asleep or after waking
- Seeming inconsolable during or after a night terror
- Appearing confused when awakened
- Sleepwalking or getting out of bed
While a child suffering from a nightmare may be easily awakened and consoled, a child suffering from a night terror is more difficult to wake up. A child who experiences night terrors may also injure themselves during sleep or suffer from bedwetting. Some researchers theorize that night terrors result from normal childhood changes, such as sleeping alone away from parents.
Treatments for night terrors include scheduled awakenings to avoid long periods spent asleep and dreaming, medications, and a machine designed to lightly vibrate when it senses night terrors beginning, awakening the child just enough to interrupt the cycle of frightening dreams.
FAQQ: What is parasomnia? A: Abnormal movements, behaviors, emotions, perceptions, or dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep.
Also known as Dream Anxiety Disorder, Nightmare Disorder causes frequent nightmares that trigger distress, disrupt sleep, interfere with daytime functioning, and/or lead to fear of falling asleep. Approximately 4% of adults in the US have nightmares frequent and disruptive enough to qualify as nightmare disorder. The disorder is considered a parasomnia.
The diagnostic criteria described in the The Diagnostic and Statistical Manual of Mental Disorders (DSM–5) are as follows:
- Repeated awakenings from sleep or naps with a detailed recollection of disturbing dreams, typically involving threats to survival, security, or well-being. The awakenings usually occur during the second half of the period of sleep
- On awakening, the person rapidly becomes oriented and alert. This contrasts with the confusion and disorientation of night terrors
- The nightmare causes distress or impairment in social and other essential areas of functioning
- The nightmares do not occur exclusively during the course of another mental disorder, and are not due to another medical condition, substance, or medication
Persistent nightmares may be classified by:
- When they occur. Do they begin with sleep onset, or later in the sleep cycle?
- Their association with a sleep disorder such as narcolepsy, another medical condition, or substance use disorder
- When they began. Nightmares that have lasted 1 month or less are considered acute, between 1 and 6 months are considered subacute, 6 months or longer are considered persistent
- Severity. Nightmares that occur on average less than once per week are considered mild, once or more per week but less than nightly are moderate, nightly are severe
Nightmare disorder sufferers may scream or shout during sleep. The disorder may be caused by many of the same conditions that cause ordinary nightmares, or may be idiopathic, or of no known cause.
The nightmares of nightmare disorder can be distinguished from ordinary nightmares by their frequency, vivid quality, and tendency to affect daytime functioning. Nightmare disorder may lead to insomnia due to chronic anxiety and the fear of falling asleep.
Sleep disorders such as narcolepsy, restless legs syndrome, and sleep apnea may cause nightmares. Sleep-wake disorders such as narcolepsy can degrade the boundaries between the sleep and wake states, causing them to overlap. These poor boundaries may cause other parasomnias, as well, such as sleep paralysis and hypnagogic hallucinations.
Restless legs syndrome and sleep apnea may interrupt REM sleep, leading to frequent awakenings as well as strange and unsettling dreams. The recollection of nightmares and other dreams may be heightened by sleep disorders due to their tendency to interrupt REM sleep.
REM sleep behavior disorder causes sufferers to act out dreams and nightmares due to loss of muscle paralysis during REM sleep. Dreamers are usually protected from such activity due to widespread muscle paralysis. When this paralysis doesn’t occur, injury and damaged surroundings may result. REM sleep behavior disorder is strongly associated with a greater risk of Parkinson’s and other degenerative neurological diseases.
Treatment of Nightmares
Treatment of nightmares may include certain types of medications, hypnosis, and desensitization therapy. Sleep professionals may also utilize variations of Cognitive Behavioral Therapy such as Self-Exposure Therapy, which allows nightmare sufferers to expose themselves to memories of disturbing dreams or events at their own pace.
Many of these types of therapies combine elements of sleep hygiene, stimulus control therapy, and other sleep treatment modalities to help nightmare sufferers address and control emotions associated with disturbing dreams. (13)
Stimulus Control Therapy, or SCTSCT helps to break conditioned negative associations with sleep and the sleeping environment. SCT protocol includes reserving the bed as a place to sleep, only going to bed when sleepy, and not napping.
One of the most effective treatments for nightmares of all types may be Imagery Rehearsal Therapy, or IRT. A type of cognitive behavioral therapy, IRT trains nightmare sufferers to alter the ending of nightmares while awake so the dream becomes non-threatening. This ending is then rehearsed for 10-20 minutes each day, becoming part of the dream narrative and changing its outcome. (14) IRT may also help to improve daytime symptoms in PTSD sufferers.
Imagery rehearsal therapy may be particularly effective for nightmares experienced by PTSD sufferers. Some studies show that the medication Prazosin helps reduce PTSD-related nightmares, while other studies show minimal to no benefit. (15) (16)
Yoga, meditation, and guided relaxation therapies may help lower stress and anxiety, reducing the fear of nightmares as well as the risk of their occurence. Cognitive behavioral therapy may help nightmare sufferers explore the emotions behind their dreams and address the fear of nightmares occurring again. A relaxing bedtime routine may also help reduce anxiety and help reduce the risk of disturbing dreams.
Strategies for helping children who experience ordinary nightmares include:
- Comfort and reassure. A calm parental presence can help a child learn to self-soothe and feel less fearful after waking from a nightmare. A favorite stuffed animal or blanket might make a child feel more secure
- Discuss the dream. Ask the child to describe the dream and who was in it. Sharing frightening dream images can help them seem less threatening
- Help the child rewrite the nightmare. Imagining a happy or funny ending to a nightmare may help diminish the dream’s power in a child’s mind, and add an element of play to the experience
- Use a night light. Darkness may frighten a child who is prone to nightmares, or make waking from a nightmare more upsetting
- Address a child’s anxiety or stress. Starting a new school, moving, the addition of a new sibling, and other life changes may disrupt a child’s sleep or increase the risk for nightmares
Last Word from Sleepopolis
Despite their negative and often frightening subject matter, nightmares may be the most vivid and well-remembered type of dream. They occur frequently in children, adolescents, and adults, and can result from a number of common psychological and medical conditions.
Though they may be disturbing, nightmares can be reduced or altered by a number of effective treatments, including altering the course of dream events and changing how they turn out. Nightmares may highlight emotions or experiences that need to be addressed, and in that way, offer enlightening glimpses into the subconscious.
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- Timothy I. Morgenthaler, MD., Position Paper for the Treatment of Nightmare Disorder in Adults: An American Academy of Sleep Medicine Position Paper, Journal of Clinical Sleep Medicine
- Kung S, Espinel Z, Lapid MI., Treatment of Nightmares With Prazosin: A Systematic Review, Mayo Clinic Proceedings, Sep. 2012
- Murray A. Raskind, M.D., Trial of Prazosin for Post-Traumatic Stress Disorder in Military Veterans, NEJM, Feb. 8, 2108