Practice Essentials
Sleep terrors (also referred to as night terrors) are a specific sleep disruption most remarkable for their intensity and anxiety-inducing nature. Several precipitating factors have been suggested, but no consistent structural or biochemical abnormality has been identified to account for all cases of sleep terrors.
Signs and symptoms
Symptoms of sleep terrors include the following:
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Sudden arousal from non–rapid eye movement (NREM) sleep, usually occurring in the first third of the night
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Associated autonomic and behavioral manifestations of fear, including crying, screaming, or thrashing
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Agitation (more commonly seen in adults)
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Significant autonomic hyperactivity, including tachycardia, tachypnea, and diaphoresis
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No or minimal response to external stimuli during the event
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Upon wakening: Confusion, disorientation, and amnesia regarding the event
There are no specific physical findings or signs found on routine physical examination when the individual is awake.
See Presentation for more detail.
Diagnosis
The diagnosis is made primarily based on a history that identifies the classic symptoms of sleep terror and by excluding other possible etiologies for the sleep disturbance based on the clinical presentation. There have been no identified irregularities in laboratory evaluation, and no additional workup is required in a classic sleep terror presentation. Further evaluation may be useful as follows:
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Sleep diary to help identify sleep patterns and triggers for sleep terrors
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Investigation of comorbidities
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Assessment for significant daytime somnolence, violent behavior during episodes, or severe distress on the part of family members
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Polysomnography for a suspected respiratory disturbance
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Routine electroencephalography (EEG) or sleep-deprived EEG if nocturnal seizures are suspected
The American Academy of Sleep Medicine's (AASM) 2014 International Classification of Sleep Disorders (3rd Edition) ciagnostic criteria for sleep terrors are as follows: [1]
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Recurrent episodes of incomplete awakening from sleep
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Inappropriate or absent responsiveness to efforts of others to intervene or redirect the person during the episode.
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Limited or no associated cognition or dream imagery
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Partial or complete amnesia for the episode
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The disturbance is not better explained by another sleep disorder, mental disorder, medication, or substance use
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The arousals are characterized by episodes of abrupt terror, typically beginning with an alarming vocalization such as a frightening scream.
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There is intense fear and signs of autonomic arousal, including mydriasis, tachycardia, tachypnea, and diaphoresis during an episode.
See Workup for more detail.
Management
Because sleep terrors are typically benign and self-limited, most affected individuals require no specific medical intervention other than reassurance and education.
Measures that may be helpful include the following:
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Appropriate treatment of associated comorbid conditions
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Promoting a stable environment with adequate regular sleep habits
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Routine follow-up and developmental assessment for affected children
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Continued support and reassurance for affected families
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Surveillance for deviation from classic sleep terror characteristics or increasing severity of behavior during episodes
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Efforts to keep affected individuals from harming themselves or others during episodes
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Scheduled awakenings
See Treatment and Medication for more detail.
Background
Sleep terrors (also known as night terrors) are a sleep disturbance characterized by waking from sleep with a fit of apparent sudden, intense distress (often indicated by a loud cry or scream). This is followed by a state of apparent panic and lack of responsiveness. The eyes are usually open during an episode, sometimes noted to have a glassy stare. Most episodes occur within the first 90 minutes after a person initiates sleep. [2] The sleep terror occurs as the person goes through stages 3 and 4 of non–rapid eye movement (NREM) sleep, though episodes may occur later or during naps. These usually emerge between 4 and 12 years of age. [1]
Diagnostic criteria
Parasomnias are sleep-wake disorders characterized by undesirable motor, verbal, or experiential phenomena occurring in association with sleep, specific stages of sleep, or sleep-awake transition phases.
There are two main sets of diagnostic criteria for sleep terrors. One from the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), [3] and one from the 2014 International Classification of Sleep Disorders, 3rd Edtiion (ICSD-3) [1] , from the American Academy of Sleep Medicine (AASM). The two are described in the table below.
Table 1. Diagnostic criteria for sleep terrors (Open Table in a new window)
| Features | DSM-5 | ICSD-3 |
|---|---|---|
| Frequency | Recurrent episodes | Recurrent episodes |
| Awakening | Abrupt arousal from sleep | Incomplete awakening from sleep |
| Responsiveness | Relative unresponsiveness | Inappropriate or absent responsiveness |
| Recall | Little or no recall of dream imagery | Little or no associated cognition or dream imagery |
| Amnesia | Amnesia of the episode | Partial or complete amnesia of the episode |
| Functional Impact | Significant distress or impairment in social, occupational, or other areas of functioning | |
| Differential | Symptoms cannot be explained by another mental disorder, medical condition, or the effects of drugs of abuse or medication | Symptoms cannot be explained by another mental disorder, medical condition, or the effects of drugs of abuse or medication |
| Initial Expression of Fear | Panicked scream | Alarming vocalization, such as a frightened scream |
| Autonomic Symptoms | Autonomic arousal | Mydriasis, tachycardia, tachypnea, diaphoresis during an episode |
Pathophysiology
Several precipitating factors for sleep terrors have been suggested, but no consistent structural or biochemical abnormality has been identified to account for all cases of sleep terrors. A dysfunction in the serotoninergic system has been suggested, owing to an association found between adolescents with migraines and a history of sleep terrors. [4] Additionally, some evidence has suggested that the serotonin precursor L-5-hydroxytryptophan and the serotonin reuptake inhibitor paroxetine can help reduce the frequency of sleep terrors. [5]
Sleep studies demonstrate that sleep terrors occur during stages 3 and 4 of non–REM (NREM) sleep. Data from a single-proton emission computed tomography (SPECT) scan in a patient with parasomnia show there was activation of the thalamocingulate pathway with persistent deactivation in the thalamocortical arousal pathway. [6, 7] In one study, 96% of the patients were found to have positive family history in first- to third degree relatives [8, 7] . In a prospective twin study, correlation was more than 0.6 for monozygotic twins compared with 0.36 and 0.24 for dizygotic twins at 18 and 36 months of age, respectively. [9, 7] A high prevalence in those with parasomnias had HLA DQB1*05 and HLA DQB1*04 alleles [10]
A strong correlation between sleep terrors and sleepwalking is noted, with a high frequency of either process in first-degree family members of individuals who experience sleep terrors.[petit] An association of sleep terrors and sleepwalking in family members of individuals with nocturnal frontal lobe epilepsy has also been reported. [11]
Etiology
No specific cause has been identified for sleep terrors. Suggested triggers have included the following: [8, 12] 11 [2, 7]
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Inadequate or irregular sleep schedule
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Unfamiliar or disruptive sleep environment (including having a TV set in a child's room)
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Travel
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Concurrent fever or illness
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A full bladder during sleep
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Generalized stress
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Obstructive sleep disorders
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Periodic limb movements
These triggers do not appear to cause sleep terrors but may lower the threshold for sleep terror events.
An association of sleep terrors and sleepwalking in family members of individuals with nocturnal frontal lobe epilepsy has also been reported. [11]
Epidemiology
It is estimated that between 1% and 6.5% of children and 2.2% of adults experience sleep terrors although prevalence is difficult to accurately assess. [1] In children younger than 3.5 years, the peak frequency is at least 1 episode per week; among older children, the peak frequency is 1–2 episodes per month. [15] The course in adults is more chronic, with significant variability in both the frequency and the severity of episodes among affected individuals. [3]
Night terrors can occur from infancy through adulthood. [16] The age range of peak frequency is 4–12 years for children and 20–30 years for adults. However, one study found peak prevalence in children at 18 months of age, indicating that previous thoughts on prevalence might be affected by lack of studies in children under two years old. [17] Most childhood-onset sleep terrors resolve by adolescence. Most sources indicate that the genders experience sleep terrors at an equal frequency; however, the APA (in DSM-5) states that the incidence is increased in male children. [3] Sleep terrors are experienced equally across racial categories. In the geriatric population prevalence of sleep terrors is slightly less than 1%. [18]
Prognosis
Most children with sleep terrors experience resolution before adolescence. No increased occurrence of psychiatric diagnoses is found in children. Adults who experience sleep terrors have an increased occurrence of other psychiatric conditions, particularly posttraumatic stress disorder (PTSD), generalized anxiety, and dependent, schizoid, and borderline personality disorders. [3, 9, 19]
As many as one third of children with sleep terrors will develop sleepwalking later in their childhood. [20]
A strong correlation between sleep terrors and sleepwalking is noted, with a high frequency of either process in first-degree famiy members of individuals who experience sleep terrors. [21]
Sleep terrors are fundamentally benign, but some affected individuals may experience trauma from interactions with their surroundings or may injure others attending them. Attempts to awaken an affected individual during an episode are generally unsuccessful and increase the potential of harm to persons offering support. [22]
Patient Education
Families and individuals must understand that sleep terrors are fundamentally benign, self-limited events. Safety measures including modifying the sleep environment to afford increased patient protection, securing windows, and limiting access to potentially harmful situations. Because the affected individual is generally unresponsive to outside interventions, aggressive attempts to intervene should be discouraged. Improvement of sleep hygiene and avoidance of potential triggers may reduce the frequency or severity of events. [12]
For patient education resources, see the Sleep Disorders Center, as well as Night Terrors, Disorders That Disrupt Sleep (Parasomnias), and REM Sleep Behavior Disorder.
Healthy Sleep
In 2016, the American Academy of Sleep Medicine (AASM) issued consensus recommendations for the amount of sleep needed to promote optimal health in children and teenagers and to avoid the health risks of insufficient sleep. [23]
To promote optimal health, the recommendations advise the following amount of sleep (per 24 hours) on a regular basis:
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Infants 4 to 12 months: 12 to 16 hours of sleep (including naps);
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Children 1 to 2 years of age: 11 to 14 hours (including naps);
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Children 3 to 5 years of age: 10 to 13 hours (including naps);
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Children 6 to 12 years of age: 9 to 12 hours; and
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Teenagers 13 to 18 years of age: 8 to 10 hours.
Tables
| Features | DSM-5 | ICSD-3 |
|---|---|---|
| Frequency | Recurrent episodes | Recurrent episodes |
| Awakening | Abrupt arousal from sleep | Incomplete awakening from sleep |
| Responsiveness | Relative unresponsiveness | Inappropriate or absent responsiveness |
| Recall | Little or no recall of dream imagery | Little or no associated cognition or dream imagery |
| Amnesia | Amnesia of the episode | Partial or complete amnesia of the episode |
| Functional Impact | Significant distress or impairment in social, occupational, or other areas of functioning | |
| Differential | Symptoms cannot be explained by another mental disorder, medical condition, or the effects of drugs of abuse or medication | Symptoms cannot be explained by another mental disorder, medical condition, or the effects of drugs of abuse or medication |
| Initial Expression of Fear | Panicked scream | Alarming vocalization, such as a frightened scream |
| Autonomic Symptoms | Autonomic arousal | Mydriasis, tachycardia, tachypnea, diaphoresis during an episode |
| Feature | Sleep Terror | Nightmare |
|---|---|---|
| Categorization | Disorder of arousal | REM parasomnia |
| Timing | Usually occurs during the first half of the night and typically out of stage N3 slow-wave sleep | Begins out of REM sleep and typically occurs in the last third of the night |
| Family history | Frequently positive | May be positive |
| Behavior semiology | Sudden arousal with intense screaming, inconsolable crying, agitation, heightened autonomic discharge | Paroxysmal awakenings with anxiety dream recall |
| Event duration | Few seconds to minutes | Few seconds to minutes |
| Age at onset | Typically < 10 years old | Typically < 10 years old |
| Triggers | Sleep deprivation, febrile illness, anxiety, stress, sleep apnea, motor disorders of sleep | Sleep deprivation, febrile illness |
| Frequency | Few times per month/week; very rarely >1 episode in a single night | Few times per month/week; very rarely >1 episode in a single night |
| Post-spell | Limited to no recall of the events with confusion | Recall is typical at times with vivid detail |
| PSG changes | Abrupt arousal from slow-wave sleep (stage N3) with expression of confusion/ambulation/intense fright in all three arousal types, followed by return to sleep; increased cyclic alternating pattern | Dense eye(phasic) movements during REM sleep |
