INTRODUCTION — Nightmares are common beginning early in childhood and extending throughout the lifespan. The condition is strongly associated with stress, anxiety, and trauma.
While nightmares are not by definition pathologic, those that are frequent or disabling and impair social, occupational, emotional, and physical wellbeing are considered a disorder and are often a sign of underlying and treatable psychopathology. Common causes include stress, negative life events, the experience of trauma as in posttraumatic stress disorder (PTSD), depression, other psychiatric disorders, and medication side effects.
This topic reviews the causes, differential diagnosis, evaluation, and management of nightmares in adults. Nightmares in children and other parasomnias in children and adults are reviewed separately. (See "Parasomnias of childhood, including sleepwalking" and "Disorders of arousal from non-rapid eye movement sleep in adults".)
EPIDEMIOLOGY — The true prevalence of nightmares and nightmare disorder is uncertain due to varying terminology and criteria for defining nightmares across studies. Nonetheless, it is clear that the occurrence of an occasional nightmare is common, and that nightmare disorder is much less common, particularly in adults.
Approximately 50 percent of children report ever having nightmares, and up to 20 percent report having frequent nightmares . Approximately 85 percent of adults report having a nightmare at least once a year, and 2 to 6 percent report having frequent (weekly) nightmares .
A large population-based study of adults over 50 years of age in Korea demonstrated a 2.7 percent prevalence of experiencing severe nightmares accompanied by awakenings . Nightmare frequency increased with age, with a more than threefold increase in the prevalence of nightmares in adults over 70 years of age (6.3 percent) when compared with adults between 50 and 70 years of age (1.8 percent). There was also an association with suicidal ideation, depression, and stress.
A systematic review of more than 100 studies found that nightmares are more commonly reported by females than males during adolescence and young adulthood (ratio of approximately 1.5 to 1) . No sex gap was present in younger children or in adults 60 years of age and older. Nightmare content and frequency, like dreams, may also vary across cultures [5,6].
CAUSES — Nightmares are more prevalent during periods of stress . They can emerge in association with traumatic experiences, as in posttraumatic stress disorder (PTSD), and in association with other psychiatric diagnoses, including depression, dissociative disorders, and borderline personality disorder. Medications most commonly associated with nightmares include those that affect norepinephrine, serotonin, dopamine, acetylcholine, or gamma-aminobutyric acid (GABA) signaling.
Trauma — Patients with a history of physical or emotional trauma are at increased risk for nightmares and related symptoms of intrusion, negative mood, dissociation, avoidance, and arousal. Possible clinical disorders include:
●Posttraumatic stress disorder (PTSD) – Nightmares with recurrent experiences of a past traumatic event are a cardinal feature of PTSD. Additional clinical features include intrusive thoughts, flashbacks, avoidance of reminders of trauma, hypervigilance, and sleep disturbance. Nightmares associated with PTSD may occur not only during rapid eye movement (REM) sleep but also at sleep onset, leading to insomnia and severe sleep disruption [8-10].
PTSD can be diagnosed based on the presence of a specified number and types of trauma-related symptoms that persist more than 30 days after the traumatic event. (See "Posttraumatic stress disorder in adults: Epidemiology, pathophysiology, clinical manifestations, course, assessment, and diagnosis", section on 'Diagnosis'.)
PTSD can occur after many types of trauma, including sexual assault, mass conflict and displacement, combat, and severe medical illnesses or injuries. Individual pre-trauma risk factors include female sex, personal and family psychiatric history, reported childhood abuse, and poor social support. (See "Posttraumatic stress disorder in adults: Epidemiology, pathophysiology, clinical manifestations, course, assessment, and diagnosis", section on 'PTSD prevalence'.)
●Acute stress disorder (ASD) – Nightmares may be accompanied by multiple trauma-related symptoms that persist for at least three days following a traumatic event and up to one month, constituting a diagnosis of acute stress disorder. (See "Acute stress disorder in adults: Epidemiology, pathogenesis, clinical manifestations, course, and diagnosis", section on 'Diagnosis'.)
●Subthreshold symptom – Nightmares secondary to trauma may present as a subthreshold symptom of PTSD or ASD that may benefit from evaluation and treatment.
Depression and other psychiatric disorders — Frequent and intense nightmares may occur in association with a wide range of psychiatric disorders, including depression, anxiety and panic disorders, schizophrenia, and borderline personality disorder . When frequent, idiopathic nightmares may have high rates of psychopathology [12,13]. Individuals with frequent nightmares are more likely to attempt suicide and self-harming behaviors [14,15].
In patients with depression, alterations in sleep architecture, including shortened REM latencies and increased density of REM sleep [16,17], may contribute to the increased rate of dysphoric dreams and nightmares. (See "Stages and architecture of normal sleep", section on 'Sleep architecture'.)
In patients with schizophrenia and other psychotic disorders, differentiating nightmares from hallucinations can sometimes be difficult, as both rely on patient report and an accurate perception of a sleep versus waking state.
Medications — A wide range of medications have been implicated in generating nightmares (table 1) [18,19]. Of note, the effect of a medication on sleep architecture, and on REM sleep specifically, does not always predict its propensity to cause nightmares. As an example, beta blocker medications tend to decrease REM sleep, but they are commonly associated with nightmares.
●Antihypertensives – In one systematic review, beta blockers accounted for one-third of the reports of nightmares as an adverse effect of medications in clinical trials . Although more common with the lipophilic beta blockers such a propranolol and metoprolol, nightmares can also be seen with hydrophilic beta-blockers such as atenolol . Reserpine has also been noted to cause nightmares.
●Dopamine agonists – Dopamine agonists can cause or worsen nightmares . This includes anti-Parkinson drugs such as levodopa, pramipexole, ropinirole, and bromocriptine as well as stimulants such as amphetamine and methylphenidate.
●Antidepressants – Antidepressant medications, although more classically associated with nightmares during medication withdrawal, can also be implicated in causing nightmares . One possible explanation for this effect is that REM sleep, although suppressed, is delayed until later in the night and associated with cholinergic rebound and more intense dream activity .
●Antimicrobials – Certain antimicrobials have also been implicated in nightmare generation, possibly through modulation of sleep-regulating inflammatory cytokines, such as interleukin (IL)-1B, tumor necrosis factor (TNF)-alpha, prostaglandin E2. Examples include ciprofloxacin, erythromycin, efavirenz, ganciclovir, and mefloquine.
●Others – More limited data, mostly in the form of case reports, implicate antihistaminergic agents, antipsychotic agents, antiseizure drugs, angiotensin-converting enzyme (ACE) inhibitors, and ketamine [18,22,23].
Withdrawal from medications — Nightmares commonly occur during withdrawal from GABA-ergic medications or substances such as alcohol, barbiturates, and benzodiazepines [8,18,19]. This is often the result of a compensatory increase in REM sleep (ie, REM rebound) that occurs when these medications, which suppress REM sleep, are withdrawn.
Similarly, withdrawal of antidepressant medications, including tricyclics, monoamine oxidase inhibitors, selective serotonin reuptake inhibitors (SSRIs), and serotonin-norepinephrine reuptake inhibitors (SNRIs), is commonly associated with increased frequency of nightmares, likely related to REM rebound.
Idiopathic — Nightmares may occur with increased frequency during times of stress or emotional instability and may disturb the quality and continuity of sleep. Some have proposed that nightmares may initially be about the experience of a stressful event but very soon are replaced by the dominant emotion of the event as a repeating narrative . The theme may be fear followed by guilt and other strong emotions.
In a Finnish nationwide twin cohort study, monozygotic twins had more similar rates of nightmares than dizygotic twins, suggesting a genetic propensity .
Nightmares — Nightmares are vivid, well-remembered dysphoric dreams that cause awakening . Dream content is typically scary and vivid, with negative themes that result in disturbed, fragmented sleep . Common themes include failure and helplessness, physical aggression, accidents, being chased, health-related concerns and death, and interpersonal conflicts [26,27].
Nightmares are often associated with a heightened sense of awareness and increased sympathetic tone as evidenced by palpitations, increased blood pressure, increased heart rate, sweating, and symptoms of anxiety and panic upon awakening. Recall of dream content is typically vivid, in contrast with sleep terrors. (See 'Differential diagnosis' below.)
Nightmares generally arise out of rapid eye movement (REM) sleep and less commonly out of N2 sleep . They occur more frequently in the last third of the night, when REM sleep predominates (figure 1). One exception is nightmares associated with post-traumatic stress disorder (PTSD), which are equally likely during N1/N2 and REM sleep and may occur both early and late in the sleep period .
Nightmare disorder — Nightmares that recur with enough frequency and distress to impact nighttime or daytime function may meet criteria for nightmare disorder. The International Classification of Sleep Disorders, Third Edition (ICSD-3), defines nightmare disorder as follows (table 2) :
●Repeated occurrences of extended, extremely dysphoric, and well-remembered dreams that usually involve threats to survival, security, or physical integrity; on awakening from the dysphoric dreams, the person rapidly becomes oriented and alert, AND
●The dream experience or sleep disturbance produced by awakening from it causes clinically significant distress or impairment in social, occupational, or other important areas of functioning as indicated by the report of at least one of the following:
•Mood disturbance (eg, persistence of nightmare affect, anxiety, dysphoria)
•Sleep resistance (eg, bedtime anxiety, fear of sleep or subsequent nightmares)
•Cognitive impairments (eg, intrusive nightmare imagery, impaired concentration or memory)
•Negative impact on caregiver or family functioning (eg, nighttime disruption), behavioral problems (eg, bedtime avoidance, fear of the dark), daytime sleepiness, fatigue or low energy, impaired occupational or educational function, or impaired interpersonal or social function.
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) definition is similar to the ICSD-3 definition but adds modifiers for duration and severity as well as two additional specifications: that the nighttime symptoms are not attributable to the physiological effects of a substance (eg, a drug of abuse or medication) and that coexisting mental and medical disorders do not adequately explain the predominant complaint of dysphoric dreams .
DSM-5 diagnostic criteria for nightmare disorder are as follows:
●A. Repeated occurrences of extended, extremely dysphoric, and well-remembered dreams that usually involve efforts to avoid threats to survival, security, or physical integrity and that generally occur during the second half of the major sleep episode
●B. On awakening from the dysphoric dreams, the individual rapidly becomes oriented and alert.
●C. The sleep disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
●D. The nightmare symptoms are not attributable to the physiological effects of a substance (eg, a drug of abuse, a medication).
●E. Coexisting mental and medical disorders do not adequately explain the predominant complaint of dysphoric dreams.
●During sleep onset
●With associated non-sleep disorder, including substance use disorders
●With associated other medical condition
●With associated other sleep disorder
●Acute – Duration of period of nightmares is ≤1 month
●Subacute – Duration of period of nightmares >1 month, <6 months
●Persistent – Duration of period of nightmares is ≥6 months
Current severity by the frequency with which the nightmares occur:
●Mild – Less than one episode per week on average.
●Moderate – One or more episodes per week but less than nightly.
●Severe – Episodes nightly.
Polysomnography — Polysomnography (PSG) is not indicated for routine evaluation of nightmares. Nightmares are less likely to occur in the sleep laboratory than in the home environment . PSG may be helpful in selected patients with atypical symptoms to investigate alternative etiologies. (See 'Differential diagnosis' below and 'Diagnostic evaluation' below.)
PSG findings in patients with frequent nightmares are inconsistent. One study using ambulatory PSG found no differences in sleep parameters between subjects with frequent nightmares and those without, although subjective sleep quality was worse in the nightmare group, and those with nightmares were more likely to complain of insomnia and daytime dysfunction . A second study using in-laboratory PSG found that nightmare sufferers had reduced sleep efficiencies, increased wakefulness after sleep onset, reduced slow wave sleep, and increased nocturnal awakenings, particularly from N2 sleep, compared with healthy controls .
Limited data suggest that periodic limb movements of sleep (PLMS) may be more frequent in patients with idiopathic nightmares and nightmares associated with posttraumatic stress disorder (PTSD) compared with healthy controls . (See "Polysomnography in the evaluation of abnormal movements during sleep", section on 'Periodic limb movements of sleep'.)
DIFFERENTIAL DIAGNOSIS — The differential diagnosis of nightmare disorder includes dysphoric dreams ("bad dreams"), other parasomnias, such as rapid eye movement (REM) sleep behavior disorder (RBD) and sleep terrors, and psychiatric disorders such as nocturnal panic attack (table 3).
Clinical features of nightmares that are helpful in differentiating them from most other sleep-related phenomena include full alertness and dream recall upon awakening, occurrence generally later in the night when REM is more frequent, and an absence of motor behavior while sleeping.
●Dysphoric dreams – Dysphoric dreams, or "bad dreams," are distinguished from nightmares by a lack of awakening from sleep . Like nightmares, bad dreams involve intense negative emotions, most often anxiety and fear . However, the content and intensity of bad dreams tends to be less comprehensively remembered in the morning, since awakening is delayed.
●REM sleep behavior disorder – RBD should be suspected when dreams or nightmares are associated with motor activity or vocalization. During normal dreaming and REM sleep, most of the major muscle groups are paralyzed (atonic), preventing movement. In RBD, there is loss of normal REM-related atonia, resulting in the ability to move and "act out" dreams.
Physical behaviors in RBD range from minor limb movements and groaning to violent thrashing, punching, and kicking movements associated with injury to the patient or bed partner. Patients often wake up briefly as a result of the movements and recall an unpleasant or threatening dream.
RBD is most commonly seen in older adults in association with neurodegenerative disorders such as dementia with Lewy bodies and Parkinson disease; however, symptoms of RBD may precede cognitive decline and motor disability by a decade or more. In younger patients, RBD may be seen in association with antidepressant medications, narcolepsy, and rarely structural brainstem pathology. (See "Rapid eye movement sleep behavior disorder".)
●Sleep terrors (pavor nocturnus) – Sleep terrors are a disorder of arousal from non-REM (NREM) sleep in which an individual suddenly sits up in bed, screams, and may flail about or walk around. There is increased sympathetic nervous system activity (eg, pupillary dilation, sweating, tachycardia), and individuals appear scared and inconsolable, even though they are not clearly aware of their surroundings.
Sleep terrors last a few minutes to as long as 30 to 40 minutes, and patients are often amnestic for the events . In contrast with nightmares, which occur during REM sleep, sleep terrors usually occur from N3 sleep (delta, slow wave, or deep sleep) and are noted in the early part of the night, when NREM sleep predominates (figure 1).
Sleep terrors are most common in children and are usually benign. In adults, they may be an indicator of comorbid posttraumatic stress disorder (PTSD), anxiety, or other psychiatric disorders . (See "Disorders of arousal from non-rapid eye movement sleep in adults".)
●Nocturnal panic attack – Patients with nocturnal panic attacks awaken from sleep with a sense of impending doom, sometimes in association with tachycardia and hyperventilation. The experience is distressing and is often perceived as a heart attack due to the intensity of physical symptoms. Nocturnal panic attacks are similar to panic attacks experienced during waking hours and often lack an identifiable trigger [37,38]. (See "Panic disorder in adults: Epidemiology, clinical manifestations, and diagnosis".)
Unlike nightmares, nocturnal panic attacks are not usually associated with recall of a dysphoric dream, and the degree of physical hyperarousal is generally greater than that associated with nightmares.
●Hypnopompic/hypnagogic hallucinations – Hallucinations upon awakening (hypnopompic hallucinations) or upon falling asleep (hypnagogic hallucinations) can sometimes be difficult to differentiate from nightmares by history. Patients awakening from a nightmare may continue to experience dream content briefly while awake, thereby mimicking a hallucination; patients who have hypnagogic hallucinations can quickly awaken and believe they had a nightmare.
Hypnopompic hallucinations are usually visual but can involve the other senses. Like nightmares, they arise out of REM sleep. Hypnopompic hallucinations are most classically associated with narcolepsy, a disorder characterized by the irrepressible need to sleep, excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic or hypnopompic hallucinations . They can also occur idiopathically or in association with other parasomnias. (See "Clinical features and diagnosis of narcolepsy in adults", section on 'Hypnagogic hallucinations' and "Approach to the patient with visual hallucinations", section on 'Narcolepsy'.)
●Bereavement-related dysphoric dreams – Negatively-themed dreams may occur during or shortly after periods of grief and loss, disrupting sleep. The triggering factor is the death or loss of a loved one, and the dreams usually occur in the context of a person who does not routinely have nightmares. Dysphoric dreams associated with bereavement are often self-limited and rarely require specific treatment [40,41]. (See "Bereavement and grief in adults: Clinical features" and "Bereavement and grief in adults: Management".)
●Lucid dreaming – Lucid dreaming occurs when an individual is aware that they are dreaming while asleep. When these dreams have negative content, they can resemble a nightmare.
●Nocturnal seizures – Rarely, nocturnal seizures are associated with frightening auras or ictal imagery that may mimic a nightmare. In most cases, these symptoms do not occur in isolation, and stereotypical motor activity and other more typical signs of seizure are present. Corroborative history from a bed partner is important, as patients may emphasize the frightening nightmare-like symptom and not be aware of other seizure manifestations. If suspicion for seizure persists, further evaluation with overnight video-electroencephalography (video-EEG) monitoring can be used to better characterize the spells. (See "Disorders of arousal from non-rapid eye movement sleep in adults", section on 'Sleep-related seizures' and "Sleep-related epilepsy syndromes".)
●Sleep-related breathing disorder – Arousals or awakenings associated with apneas and hypopneas may appear frightening to a bed partner, who may report that the patient is having "scary dreams." Similarly, patients may awaken from a REM-related respiratory event with choking or gasping and either have a perception of a frightening dream or recount a co-occurring nightmare (for example, about drowning). In such cases, the primary disorder is sleep apnea, and dysphoric dreams are often secondary. This can be differentiated from nightmare disorder by history and polysomnography (PSG). (See "Clinical presentation and diagnosis of obstructive sleep apnea in adults".)
DIAGNOSTIC EVALUATION — Nightmare disorder is a clinical diagnosis (table 2). A comprehensive clinical evaluation aims to differentiate nightmares from mimics (table 3), identify causes and contributing factors, and assess the impact on physical, social, and emotional functioning.
Key components of the history include the following:
●Description of nightmares, including frequency and duration.
●Assessment of sleep quality, quantity, and any abnormal movements or behaviors during sleep.
●Potential contributing factors, such as medications, substances (table 1), and recent or past stressful life events.
●A history of experiencing a traumatic event.
•The posttraumatic stress disorder (PTSD) checklist (PCL-5) can be used to screen patients for PTSD (table 4). Patients with possible PTSD should receive a comprehensive psychiatric assessment. (See "Posttraumatic stress disorder in adults: Epidemiology, pathophysiology, clinical manifestations, course, assessment, and diagnosis".)
●Signs and symptoms of relevant comorbidities, including depression and other psychiatric disorders.
•Patients can be screened for depression with the self-report, two-item Patient Health Questionnaire (PHQ-2) (table 5), and those who screen positive should be interviewed to diagnose depression. The interview can be facilitated with the self-administered PHQ-9 (table 6). Other commonly used tools include the Beck Depression Inventory, the Structured Clinical Interview for DSM Disorders (SCID), and Hamilton Depression Rating Scale (HAMD) (table 7). (See "Screening for depression in adults", section on 'Screening instruments' and "Unipolar depression in adults: Assessment and diagnosis".)
●Adverse consequences on sleep and daytime function.
Polysomnography (PSG) is not indicated to confirm the diagnosis of nightmares or nightmare disorder. PSG may be indicated if a primary sleep disorder is suspected such as rapid eye movement (REM) sleep behavior disorder (RBD) or obstructive sleep apnea. (See 'Differential diagnosis' above and "Overview of polysomnography in adults".)
General approach — Nightmares do not always require treatment. Even individuals who meet criteria for nightmare disorder may find that symptoms resolve over time without specific intervention. For patients who require intervention, we recommend a top-down approach, starting with a broad general evaluation of sleep and any predisposing trauma, psychiatric disorders or medications and then moving on to more specific treatment of nightmares when needed.
For patients who require nightmare-specific treatment, clinical guidelines from the American Academy of Sleep Medicine (AASM) endorse both behavioral and pharmacologic approaches . Among these, imagery rehearsal therapy (IRT), a form of cognitive behavioral therapy (CBT), and prazosin have the largest supporting literature. Both have been primarily studied in patients with posttraumatic stress disorder (PTSD), who often have stereotyped, repeated nightmares and additional symptoms of hyperarousal, and trial results of prazosin have been inconsistent. (See 'Prazosin' below.)
The choice between psychotherapy and medication can be individualized according to patient preferences and access to a therapist. In our experience, the majority of chronic persistent nightmares in adults are related in some way to underlying psychopathology or past trauma, and we encourage most patients to engage in psychotherapy prior to or in conjunction with prazosin.
Lifestyle modification and good sleep hygiene — Lifestyle modifications that promote good sleep can help to decrease the frequency and severity of nightmares and enhance the overall quality of sleep. These interventions have demonstrated efficacy in treating nightmares in children and young adults .
Although sleep hygiene has not been studied on its own in patients with nightmare disorder, it is often a component of studies involving other treatments  and is a low-cost, low-risk intervention. (See 'Nightmare-focused psychotherapy' below.)
Good practice recommendations include the following:
●Seek out healthy social interaction to promote emotional stability and sense of wellbeing.
●Take a warm shower and empty the bladder prior to sleep.
●Exercise regularly, but not within four hours of sleep time.
●Avoid greasy fatty foods close to bedtime. Do not skip meals, as hunger may influence sleep quality.
●Avoid alcohol, caffeine, and nicotine close to bedtime.
●Keep a consistent schedule for sleep and daytime function.
●Sleep in a comfortable environment that is conducive to good sleep (appropriate bedding, temperature, noise levels, etc).
●Establish a healthy, relaxing bedtime routine.
●Avoid television, computers, and screens (such as smart phones or tablets) for at least an hour before bedtime.
●Use bed only for sleep and intimacy (stimulus control).
Withdrawal of causative medications — When the onset of nightmares is temporally linked to a potentially causative medication (table 1), discontinuation of or gradual decrease in dose will usually result in resolution of the nightmares. Other etiologies and interventions discussed below should be pursued if nightmares do not resolve with discontinuation of the medication.
Treatment of co-occurring psychiatric disorders — Psychiatric assessment and treatment of underlying psychiatric disease are recommended in patients with persistent nightmares. Successful treatment of common predisposing conditions such as stress, anxiety, depression, acute stress disorder (ASD) or PTSD will often decrease the frequency and severity of nightmare disorder. This may be accomplished in the primary care setting or through referral to a mental health clinician, depending on the severity of psychiatric symptoms and comfort level of the treating clinician.
However, even with successful treatment of predisposing factors and co-occurring psychiatric disorders, nightmares can persist and may require specific treatment .
Nightmare-focused psychotherapy — Psychotherapy to address underlying psychopathology or past trauma is suggested in most patients with chronic, persistent nightmares. Psychotherapeutic interventions for nightmare disorder focus on exposure and stress management using cognitive and behavioral techniques, which are tailored to assess, identify, modify, and correct distortions of cognition and behavior [46,47]. (See "Psychotherapy and psychosocial interventions for posttraumatic stress disorder in adults", section on 'Exposure-based therapies'.)
A variety of cognitive and behavioral approaches have been studied for patients with nightmare disorder (table 8). Among these, we suggest imagery rehearsal therapy (IRT), a form of cognitive behavioral therapy (CBT), in most patients. IRT may be most applicable in patients with a recurring nightmare or schema (table 9). If IRT is not available, more limited data support other forms of CBT tailored to nightmares.
CBT is a specialized short-term, goal-oriented psychotherapeutic approach that focuses on distorted or dysfunctional beliefs, thoughts, emotions, and associated behaviors that influence nightmares [48-54]. The cognitive component focuses on distorted thinking, emotions, feelings, and their associated influence on nightmares and sleep disruption. The behavioral component is tailored to address maladaptive behaviors and actions that influence poor sleep and perpetuate nightmares. CBT alone is effective in the treatment of nightmares, although more specialized nightmare-focused treatment variants like CBT-I, IRT, and exposure, relaxation, and rescripting therapy (ERRT) have improved results.
●Imagery rehearsal therapy – IRT is a specialized, trauma-focused intervention targeting nightmare disorder (table 9) [55,56]. It includes CBT techniques of initially recalling the nightmare and negative event, writing it down with details of emotional sensitivity, reading it, and then modifying the theme. The modified story is made more favorable, and the ending of the story line is changed and rewritten. The rewritten dream is then rehearsed so that the modified, more acceptable dream content will replace the nightmare if the dream recurs. This technique aims at rescripting the content and theme of the nightmare to decrease the negative emotion from the dream, rendering it bearable or even favorable to the patient [57,58]. This technique requires expertise by the therapist and practice by the patient for success.
IRT has shown efficacy in patients with both idiopathic nightmare disorder as well as trauma-associated nightmare disorder [42,59]. In a meta-analysis of 11 randomized trials of IRT alone or combined with other psychological treatments for nightmares in patients with PTSD, IRT showed moderate positive effects on nightmare frequency and sleep quality compared with a control condition . Studies assessing the efficacy of IRT with CBT-I have shown mixed results. One trial in 108 war veterans with PTSD-associated nightmares found no added benefit of IRT when combined with CBT-I compared with CBT-I alone . Another smaller RCT of 42 sexual assault victims with PTSD showed benefit with IRT with no additional benefit when IRT was followed by general CBT .
More limited data suggest that an online delivery model may be a viable way to expand access to IRT. In one trial involving 127 participants with nightmare disorder, mostly idiopathic, those randomly assigned to online IRT demonstrated a decrease in distress compared with those assigned to a control condition (simple tracking of nightmare narratives); nightmare frequency was similar between groups . Further work needs to be done to standardize the online model and validate it in different languages.
●Cognitive behavioral therapy for insomnia – CBT-I is a specialized and focused cognitive and behavioral intervention to manage distorted and dysfunctional sleep beliefs and behaviors [51,52]. The goal is to help improve quality and quantity of sleep, with consequent reduction of frequency and severity of nightmares.
Two randomized trials of veterans with PTSD-related nightmares demonstrated improvement, but in certain areas results were mixed. In one study, veterans who were randomly assigned to CBT-I over wait-list controls showed significant improvement in Pittsburgh Sleep Quality Index Addendum for PTSD (PSQI-A) scores, which includes a measure of nightmares, but both the CBT-I group and wait-list controls had a similar decrease in nightmares on the Clinician-Administered PTSD Scale (CAPS) distressing dreams item . No adverse effects were reported and the improvements were sustained following treatment. As mentioned in the discussion of IRT, a study of veterans with PTSD-associated nightmares using both CBT-I and IRT found CBT-I alone to be as effective in nightmare reduction as CBT-I combined with the nightmare-specific IRT .
●Other specialized techniques – More limited data support other forms of CBT tailored for nightmares . These include systematic desensitization; progressive deep muscle relaxation training; lucid dreaming therapy; sleep dynamic therapy; self-exposure therapy; ERRT; hypnosis; and eye movement desensitization and reprocessing (EMDR). The effectiveness of these interventions depends on the expertise of the therapist and the acceptance by the patient.
Prazosin — Prazosin, an alpha-1 adrenergic receptor antagonist, is the best studied medication for nightmares and has been the preferred first-line pharmacotherapy when medication is deemed necessary . Trials of prazosin in patients with PTSD published subsequent to the AASM literature review  have had conflicting results, however [64,65].
While prazosin remains a reasonable option in patients with nightmares who fail or do not have access to nightmare-focused psychotherapy, further studies are needed to help identify patients who are most likely to respond to prazosin. There is a paucity of data on prazosin and other drugs for patients with idiopathic nightmare disorder.
A 2020 meta-analysis of seven randomized trials in 528 patients with PTSD found that prazosin was more effective than placebo at improving nightmares, sleep quality, and illness severity, with moderate to large effect sizes . Most patients were treated concurrently with psychotherapy and psychiatric medications such as selective serotonin reuptake inhibitors (SSRIs). There was significant between-study heterogeneity. In particular, the largest individual trial in 304 veterans with PTSD and frequent nightmares failed to show benefits of prazosin compared with placebo in alleviating distressing dreams or improving sleep quality . Several limitations of this trial have been raised as potential explanations for the discrepant results with prior trials, including a high percentage of antidepressant use in both arms and the exclusion of patients with psychosocial instability, which may have excluded more severely affected patients who were most likely to respond to adrenergic blockade. This was supported by lower mean blood pressures than expected in the trial participants, relatively low rates of benzodiazepine and alcohol use, low study attrition, and low use of additional treatments after week 10.
Prazosin is typically started at 1 mg at bedtime and the dose gradually increased at intervals ranging from a few days to weekly as tolerated [64,67]. The recommended target dose from the Veteran's Administration is 6 to 10 mg ; however, efficacy can be seen at lower doses, which may be preferable in low body weight and older individuals. Across trials, effective, tolerated mean doses range from 3 to 16 mg, with most studies using final doses in the 10 to 15 mg range [59,69,70]. Use of a low starting dose and slow titration minimizes the incidence of side effects such as hypotension and syncope [71,72].
Treatment effect takes weeks to occur, with most studies showing efficacy by eight weeks. Improvement can be seen earlier, however . Duration of treatment should be individualized based on trajectory of response and any adverse events. Once the patient has experienced relief of symptoms for a sustained period of time, one can begin a gradual taper of the medication with close clinical follow-up. Patients who fail to respond to prazosin may benefit from further psychotherapy.
The mechanism of effect of prazosin in nightmare disorder may relate to its ability to blunt the noradrenergic nervous system, which has been implicated in the hyperarousal state of PTSD . In patients with PTSD, there is evidence for increased sensitization of the noradrenergic nervous system  and elevated levels of norepinephrine in the cerebrospinal fluid .
Other drugs — Data are much more limited for other medications in the treatment of nightmares. As with prazosin, data are drawn primarily from patients with PTSD. Drugs with possible benefit in these patients include trazodone , gabapentin , clonidine , topiramate [7,42,73], terazosin, and atypical antipsychotics such as olanzapine  and risperidone .
One small, blinded cross-over randomized trial suggested that nabilone, a synthetic cannabinoid, is effective for treating PTSD-associated nightmares in military personnel, but more data are needed . Another small randomized trial found that hydroxyzine was more effective than placebo for reducing nightmares, but less effective than prazosin .
Investigational — A prescription smartwatch device called "Nightware" was authorized for marketing by the US Food and Drug Administration (FDA) in 2020 based on preliminary pilot data showing an improvement in sleep quality relative to baseline in adults with nightmare disorder or nightmares associated with PTSD [77,78]. There are no controlled data yet published upon which to assess clinical utility, including on nightmares. If randomized trials validate efficacy, the device could represent a low-risk nonpharmacologic treatment option.
According to the manufacturer, the device is designed to deliver vibrotactile feedback during a nightmare episode in order to produce a micro-arousal. It uses a machine-learning algorithm to detect changes in sleep physiology suggestive of nightmares, based on variables such as heart rate and motion. In data submitted to the FDA, there were no adverse events related to the device, and there was no evidence of an increase in daytime sleepiness .
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Parasomnias, hypersomnias, and circadian rhythm disorders".)
SUMMARY AND RECOMMENDATIONS
●Definition – Nightmares are dreams with negative content. Occasional nightmares are common, particularly in children. Nightmares decrease in frequency with age and are more commonly reported by females than males in adulthood. (See 'Epidemiology' above.)
Nightmare disorder refers to recurring nightmares with enough frequency and distress to impact nighttime or daytime function (table 2). (See 'Clinical features' above.)
●Causes – In adults, the most common conditions associated with recurrent nightmares are acute stress disorder, posttraumatic stress disorder (PTSD), depression, and anxiety. Certain medications and substances can induce or exacerbate nightmares, during either treatment or withdrawal (table 1). (See 'Causes' above.)
●Differential diagnosis – The differential diagnosis of nightmares includes other parasomnias, such as sleep terrors and rapid eye movement (REM) sleep behavior disorder (RBD), and psychiatric disorders such as nocturnal panic attack (table 3). (See 'Differential diagnosis' above.)
●Diagnostic evaluation – Nightmare disorder is a clinical diagnosis. A comprehensive clinical evaluation aims to differentiate nightmares from mimics, identify causes such as a history of trauma, and assess the impact on physical, social, and emotional functioning. (See 'Diagnostic evaluation' above.)
Polysomnography (PSG) is not indicated to confirm the diagnosis but may be useful when there is clinical suspicion for a primary sleep disorder such as RBD or obstructive sleep apnea. (See 'Diagnostic evaluation' above.)
●Initial management – Lifestyle modifications that promote good sleep can help to decrease the frequency and severity of nightmares and enhance the overall quality of sleep. Medications that may be triggering nightmares should be reduced or discontinued if possible (table 1). (See 'Lifestyle modification and good sleep hygiene' above and 'Withdrawal of causative medications' above.)
Psychiatric assessment and treatment of underlying psychiatric disease is recommended in patients with persistent nightmares. Nightmares often improve with successful treatment of the primary psychiatric disorder (eg, anxiety, depression, PTSD). (See 'Treatment of co-occurring psychiatric disorders' above.)
●Severe and chronic nightmares – Treatments include psychotherapy and medication. The choice can be individualized according to patient preferences and access to a therapist. In our experience, the majority of chronic persistent nightmares in adults are related in some way to underlying psychopathology or past trauma, and we encourage patients to engage in psychotherapy prior to or in conjunction with medication. (See 'General approach' above.)
•When psychotherapy is chosen, we suggest imagery rehearsal therapy (IRT), a form of cognitive behavioral therapy (CBT) (Grade 2C). IRT may be most applicable in patients with a recurring nightmare or schema (table 9); if IRT is not available, more limited data support other forms of CBT tailored to nightmares. (See 'Nightmare-focused psychotherapy' above.)
•When medication is chosen, we suggest treatment with prazosin (Grade 2C). Prazosin has primarily been studied in patients with PTSD-associated nightmares, and trials in this population have had conflicting results. If there are co-occurring psychiatric illnesses such as anxiety, psychosis, or depression, interventions targeted to these disorders should be initiated prior to consideration of prazosin. (See 'Prazosin' above.)
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12 : The underlying emotion and the dream relating dream imagery to the dreamer's underlying emotion can help elucidate the nature of dreaming.
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44 : An open-label trial of evidence-based cognitive behavior therapy for nightmares and insomnia in crime victims with PTSD.
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50 : Change in sleep symptoms across Cognitive Processing Therapy and Prolonged Exposure: a longitudinal perspective.
51 : Case series utilizing exposure, relaxation, and rescripting therapy: impact on nightmares, sleep quality, and psychological distress.
53 : A pilot randomized controlled trial of cognitive behavioral treatment for trauma-related nightmares in active duty military personnel.
54 : Cognitive Behavioural Therapy for Nightmares for Patients with Persecutory Delusions (Nites): An Assessor-Blind, Pilot Randomized Controlled Trial.
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67 : A parallel group placebo controlled study of prazosin for trauma nightmares and sleep disturbance in combat veterans with post-traumatic stress disorder.
68 : A parallel group placebo controlled study of prazosin for trauma nightmares and sleep disturbance in combat veterans with post-traumatic stress disorder.
69 : A trial of prazosin for combat trauma PTSD with nightmares in active-duty soldiers returned from Iraq and Afghanistan.
70 : Prazosin effects on objective sleep measures and clinical symptoms in civilian trauma posttraumatic stress disorder: a placebo-controlled study.
74 : The alpha1-adrenergic antagonist prazosin improves sleep and nightmares in civilian trauma posttraumatic stress disorder.
76 : The efficacy of nabilone, a synthetic cannabinoid, in the treatment of PTSD-associated nightmares: A preliminary randomized, double-blind, placebo-controlled cross-over design study.