REM sleep behavior disorder. The presence of complex motor activity during fright- ening dreams should prompt further evaluation for REM sleep behavior disorder, which occurs more typically among late middle-age males and, unlike nightmare disorder, is as- sociated with often violent dream enactments and a history of nocturnal injuries. The dream disturbance of REM sleep behavior disorder is described by patients as nightmares but is controlled by appropriate medication.
Bereavement. Dysphoric dreams may occur during bereavement but typically involve loss and sadness and are followed by self—reﬂection and insight, rather than distress, on awakening.
Narcolepsy. Nightmares are a frequent complaint in narcolepsy, but the presence of ex- cessive sleepiness and cataplexy differentiates this condition from nightmare disorder.
Nocturnal seizures. Seizures may rarely manifest as nightmares and should be evalu- ated with polysomnography and continuous video electroencephalography. Nocturnal seizures usually involve stereotypical motor activity. Associated nightmares, if recalled, are often repetitive in nature or reﬂect epileptogenic features such as the content of diurnal auras (e.g., unmotivated dread), phosphenes, or ictal imagery. Disorders of arousal, espe- cially confusional arousals, may also be present.
Breathing-related sleep disorders. Breathing-related sleep disorders can lead to awaken- ings with autonomic arousal, but these are not usually accompanied by recall of nightmares.
Panic disorder. Attacks arising during sleep can produce abrupt awakenings with au- tonomic arousal and fearfulness, but nightmares are typically not reported and symptoms are similar to panic attacks arising during wakefulness.
Sleep-related dissociative disorders. Individuals may recall actual physical or emo- tional trauma as a ”dream" during electroencephalography-documented awakenings.
Medication or substance use. Numerous substances/medications can precipitate night- mares, including dopaminergics; beta—adrenergic antagonists and other antihypertensives; amphetamine, cocaine, and other stimulants; antidepressants; smoking cessation aids; and melatonin. Withdrawal of REM sleep—suppressant medications (e.g., antidepressants) and alcohol can produce REM sleep rebound accompanied by nightmares. If nightmares are sufficiently severe to warrant independent clinical attention, a diagnosis of substance/ medication—induced sleep disorder should be considered.
Nightmares may be comorbid with several medical conditions, including coronary heart disease, cancer, parkinsonism, and pain, and can accompany medical treatments, such as he- modialysis, or withdrawal from medications or substances of abuse. Nightmares frequently are comorbid with other mental disorders, including PTSD; insomnia disorder; schizophrenia; psychosis; mood, anxiety, adjustment, and personality disorders; and grief during be- reavement. A concurrent nightmare disorder diagnosis should only be considered when in- dependent clinical attention is warranted (i.e., Criteria A—C are met). Otherwise, no separate diagnosis is necessary. These conditions should be listed under the appropriate comorbid category specifier. However, nightmare disorder may be diagnosed as a separate disorder in individuals with PTSD if the nightmares are temporally unrelated to PTSD (i.e., preceding other PTSD symptoms or persisting after other PTSD symptoms have resolved).
Nightmares are normally characteristic of REM sleep behavior disorder, PTSD, and acute stress disorder, but nightmare disorder may be independently coded if nightmares preceded the condition and their frequency or severity necessitates independent clinical attention. The latter may be determined by asking whether nightmares were a problem before onset of the other disorder and whether they continued after other symptoms had remitted.
Relationshlp to International Ciassification of
The International Classification of Sleep Disorders, 2nd Edition (ICSD-Z), presents similar di- agnostic criteria for nightmare disorder.