Diagnostic Features

The essential feature of Nightmare Disorder is the repeated occurrence of frightening dreams that lead to awakenings from sleep (Criterion A). The individual becomes fully alert on awakening (Criterion B). The frightening dreams or sleep interruptions resulting from the awakenings cause the individual significant distress or result in social or occupational dysfunction (Criterion C). This disorder is not diagnosed if the nightmares occur exclusively during the course of another mental disorder or are due to the direct physiological effects of a substance (e.g., a drug of abuse or a medication) or a general medical condition (Criterion D).

Nightmares typically occur in a lengthy, elaborate dream sequence that is highly anxiety provoking or terrifying. Dream content most often focuses on imminent physical danger to the individual (e.g., pursuit, attack, injury). In other cases, the perceived danger may be more subtle, involving personal failure or embarrassment. Nightmares that occur after traumatic experiences may replicate the original dangerous or threatening situation, but most nightmares do not recount actual events. On awakening, individuals with this disorder can describe the dream sequence and content in detail. Individuals may report multiple nightmares within a given night, often with a recurrent theme. Nightmares arise almost exclusively during rapid eye movement (REM) sleep. Because REM episodes occur periodically throughout nocturnal sleep (approximately every 90-110 minutes), nightmares may also occur at any time during the sleep episode. However, because REM sleep periods typically become longer and dreaming more intense in the second half of the night, nightmares are also more likely to occur later in the night.

Nightmares usually terminate with an awakening that is associated with a rapid return of full alertness and a lingering sense of fear or anxiety. These factors often lead to difficulty returning to sleep. Nightmare Disorder causes significant subjective distress more often than it causes demonstrable social or occupational impairment. However, if nocturnal awakenings are frequent, or if the individual avoids sleeping because of fear of nightmares, the individual may experience excessive sleepiness, poor concentration, depression, anxiety, or irritability that can disrupt daytime functioning.

Associated Features and Disorders

Associated descriptive features and mental disorders. In individuals with Nightmare Disorder, mild autonomic arousal (e.g., sweating, tachycardia, tachypnea) may be evident on awakening. Individuals who have had frequent nightmares since childhood tend to show elevated rates of general psychopathology on symptom measures. Depressive and anxiety symptoms that do not meet criteria for a specific diagnosis are common among individuals with Nightmare Disorder. Body movements and vocalization are not characteristic of Nightmare Disorder because of the loss of skeletal muscle tone that normally occurs during REM sleep. When talking, screaming, or striking out do occur, these are most likely to appear as brief phenomena that terminate a nightmare. These behaviors are also more likely to occur in the nightmares that accompany Posttraumatic Stress Disorder, because these nightmares may occur during non-rapid eye movement (NREM) sleep.

Associated laboratory findings. Polysomnographic studies demonstrate abrupt awakenings from REM sleep that correspond to the individual’s report of nightmares. These awakenings usually occur during the second half of the night. In most cases, the REM sleep episode will have lasted for more than 10 minutes and may include a greater-than-average number of eye movements. Heart rate and respiratory rate may increase or show increased variability before the awakening. Nightmares following traumatic events (e.g., in individuals with Posttraumatic Stress Disorder) may arise during NREM sleep, particularly stage 2, as well as during REM sleep. Other polysomnographic features, including sleep continuity and sleep architecture, are not characteristically abnormal in Nightmare Disorder.

Specific Culture, Age, and Gender Features

The significance attributed to nightmares may vary with cultural background. For instance, some cultures may relate nightmares to spiritual or supernatural phenomena, whereas others may view nightmares as indicators of mental or physical disturbance. Because nightmares frequently occur during childhood, this diagnosis should not be given unless there is persistent significant distress or impairment that warrants independent clinical attention. Nightmare Disorder is most likely to appear in children exposed to severe psychosocial stressors. Although specific dream content may reflect the age of the individual having the nightmares, the essential features of the disorder are the same across age groups. Females report having nightmares more often than do men, at a ratio of approximately 2:1 to 4:1. It is not clear to what extent this difference reflects a true discrepancy in the number of nightmares as opposed to a variance in reporting.

Prevalence

Between 10% and 50% of children ages 3-5 years have nightmares of sufficient intensity to disturb their parents. In the adult population, as many as 50% of individuals may report at least an occasional nightmare. In young adults, at least 3% report having nightmares frequently or always. However, the actual prevalence of Nightmare Disorder is unknown.

Course

Nightmares often begin between ages 3 and 6 years. When the frequency is high (e.g., several per week), the dreams may become a source of concern and distress to both children and parents. Most children who develop a nightmare problem outgrow it. In a minority, the dreams may persist at high frequency into adulthood, becoming virtually a lifelong disturbance. Adults with chronic nightmares report similar degrees of subjective sleep disturbance as those who have had nightmares for less than 6 months. A tendency toward amelioration of the disorder in later decades has been described.

Differential Diagnosis

Nightmare Disorder should be differentiated from Sleep Terror Disorder. Both disorders include awakenings or partial awakenings with fearfulness and autonomic activation, but can be differentiated by several clinical features. Nightmares typically occur later in the night during REM sleep and produce vivid dream imagery, complete awakenings, mild autonomic arousal, and detailed recall of the event. Sleep terrors typically arise in the first third of the night during stage 3 or 4 NREM sleep and produce either no dream recall or single images without the storylike quality that is typical of nightmares. Sleep terrors lead to partial awakenings in which the individual is confused, disoriented, and only partially responsive and has significant autonomic arousal. In contrast to Nightmare Disorder, the individual with Sleep Terror Disorder has amnesia for the event on awakening in the morning.

Breathing-Related Sleep Disorder can lead to awakenings with autonomic arousal, but these are not accompanied by recall of frightening dreams. Nightmares are a frequent complaint of individuals with Narcolepsy, but the presence of excessive sleepiness and cataplexy differentiates this condition from Nightmare Disorder. Panic Attacks arising during sleep can also produce abrupt awakenings with autonomic arousal and fearfulness, but the individual does not report frightening dreams and can identify these symptoms as consistent with other Panic Attacks. The presence of complex motor activity during frightening dreams should prompt further evaluation for other Sleep Disorders, such as “REM sleep behavior disorder” (see Parasomnia Not Otherwise Specified).

Numerous medications that affect the autonomic nervous system can precipitate nightmares. Examples include l-dopa and other dopaminergic agonists; beta-adrenergic antagonists and other antihypertensive medications; amphetamine, cocaine, and other stimulants; and antidepressant medications. Conversely, withdrawal of medications that suppress REM sleep, such as antidepressant medications and alcohol, can lead to a REM sleep “rebound” accompanied by nightmares. If the nightmares are sufficiently severe to warrant independent clinical attention, a diagnosis of Substance-Induced Sleep Disorder, Parasomnia Type, may be considered. Nightmare Disorder also should not be diagnosed if the disturbing dreams arise as a direct physiological effect of a general medical condition (e.g., central nervous system infection, vascular lesions of the brain stem, general medical conditions causing delirium). If the nightmares are sufficiently severe to warrant independent clinical attention, Sleep Disorder Due to a General Medical Condition, Parasomnia Type, may be considered. Although nightmares may frequently occur during a delirium, a separate diagnosis of Nightmare Disorder is not given.

Nightmares occur frequently as part of other mental disorders (e.g., Posttraumatic Stress Disorder, Schizophrenia, Mood Disorders, other Anxiety Disorders, Adjustment Disorders, and Personality Disorders). If the nightmares occur exclusively during the course of another mental disorder, the diagnosis of Nightmare Disorder is not given.

Many individuals experience an occasional, isolated nightmare. Nightmare Disorder is not diagnosed unless the frequency and severity of nightmares result in significant distress or impairment.

Relationship to the International Classification of Sleep Disorders

Nightmare Disorder corresponds to the diagnosis of Nightmares in the International Classification of Sleep Disorders (ICSD).

Diagnostic criteria for 307.47 Nightmare Disorder

A. Repeated awakenings from the major sleep period or naps with detailed recall of extended and extremely frightening dreams, usually involving threats to survival, security, or self-esteem. The awakenings generally occur during the second half of the sleep period.
B. On awakening from the frightening dreams, the person rapidly becomes oriented and alert (in contrast to the confusion and disorientation seen in Sleep Terror Disorder and some forms of epilepsy).
C. The dream experience, or the sleep disturbance resulting from the awakening, causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
D. The nightmares do not occur exclusively during the course of another mental disorder (e.g., a delirium, Posttraumatic Stress Disorder) and are not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.

References
American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders: DSM-IV-TR. Washington, DC: Author.
Hare, R.D., Hart, S.D., Harpur, T.J. Psychopathy and the DSM—IV Criteria for Nightmare Disorder