What are night terrors and why do they happen?
While people talk about "night terrors," this is not, in fact, a diagnosable condition, according to the Diagnostic and Statistical Manual fifth edition (DSM-V).
It contains elements of conditions known as nightmare disorder, REM sleep behavior disorder, and Non-Rapid Eye Movement (NREM) Sleep Arousal Disorder.
To find out more about REM sleep behavior disorder, click here.
Although nightly episodes can be terrifying, night terrors are not normally a sign of anything more serious. They tend to end as abruptly as they begin.
Here are some key points about night terrors. More detail is in the main article.
- Night terrors are most common in children, but they can happen at any age.
- They usually stop without medical intervention.
- Research shows that there may be a genetic component to night terrors.
- Some simple techniques can minimize the impact of night terrors.
- Sleepwalking often accompanies night terrors.
- Night terrors occur in the first few hours of sleep, whereas normal nightmares occur towards the end of a night's sleep.
What are night terrors?
During night terrors, a person may stare wide eyed in fear, even though they are asleep.
Night terrors are nocturnal episodes that cause great fear while sleeping. The person may flail their limbs and scream and shout.
Night terrors are most common in children, but adults can also suffer from them. A normal attack typically lasts between 30 seconds and 3 minutes, but they can be substantially longer.
Night terrors are unpleasant, but they are not usually a cause for medical concern.
They are estimated to affect some 40 percent of children, and a smaller number of adults.
Night terrors differ from nightmares. In a nightmare, the dreamer may wake up, but during night terrors they will usually stay asleep.
This difference is most likely due to the phase of sleep in which night terrors occur.
Nightmares tend to happen during rapid eye movement sleep (REM), towards the end of a night's sleep.
In contrast, night terrors occur during the first third of the night during deeper sleep, also known as slow-wave sleep or non-REM sleep.
The signs of a night terror episode can include:
- screaming and shouting
- sitting up in bed or sleepwalking
- kicking and thrashing of limbs
- heavy breathing, racing pulse, and profuse sweating
- dilated pupils and increased muscle tone
- being hard to waken
- confusion on waking
- staring wide-eyed, as if awake, but not responding to stimuli
- aggressive behavior, especially in adults)
- not remembering the event
If the person does remember the dream, it will probably involve something very frightening for them.
A number of factors may contribute to night terrors.
- fever, especially in children
- sleep deprivation
- light or noise
- an overfull bladder
- spending the night somewhere unfamiliar
- possibly, genetic factors
- migraine headaches
- physical or emotional stress
- use or abuse of some medications or alcohol
In 2014, a study of almost 7,000 children aged 8 to 10 years, with a follow-up around age 13, showed that those who were bullied were more than twice as likely to experience night terrors.
In addition, night terrors are often associated with other underlying conditions, such as breathing problems while sleeping, for example, apnea, migraines, head injuries, restless leg syndrome and certain medications.
A study that assessed 661 people with Parkinson's disease, aged 43 to 89 years, reported that 3.9 percent had night terrors. In addition, 17.2 percent had nightmares and 1.8 percent experienced sleepwalking.
The following factors may also play a role.
Night terrors and sleepwalking appear to be associated. They both occur during slow-wave sleep, the deepest sleep stages, that happen in the early part of the night.
Some researchers believe that people who experience sleepwalking or night terrors may have difficulty in maintaining slow-wave sleep. This makes them susceptible to quick arousals, and it increases the chance of parasomnias.
Brain lesions are an unlikely cause of night terrors. In some cases, however, damage to or dysfunction of the thalamus has been linked to this phenomenon.
In one study, a woman began having regular night terrors at the age of 48 years.
She underwent observation in a sleep laboratory to investigate the cause. The tests showed an increased signal coming from the thalamus. This appeared to cause the micro-arousals suggestive of night terrors.
The thalamus is thought to play a key role in maintaining sleep-wake cycles. It also acts to dampen of the signals that normally arrive from the senses, including those of hearing, while we sleep.
Most of the information our brain receives from the outside world passes through the thalamus before it is sent out to the parts of the brain that enable us to see or hear, for example.
When we sleep, the thalamus is less inclined to send this information to the rest of the brain.
As a result, when we sleep, we are less aware of tactile stimuli and the sounds around us.
People who have night terrors or who sleep walk often have a family member who also does this.
In 1980, a small study found that that 80 percent of sleepwalkers and 96 percent of people who have night terrors have at least one other close family member who has one or both conditions.
Another investigation that focused on identical and non-identical twins supported this finding.
The researchers found that a person is significantly more likely to experience night terrors if their identical twin does. In non-identical twins, the chance of this happening is lower.
A long-term study of 1,940 children, published in 2015, found that those whose parents had walked in their sleep were more likely to have night terrors and that these night terrors were more likely to persist for longer.
The peak age for night terrors in childhood was found to be 18 months. At this age, 34.4 percent of children were reported by parents to have night terrors. Up to a third of children who experienced night terrors then develop sleepwalking habits later in childhood.
Tests and diagnosis
A doctor will ask a patient and, if appropriate, family members, about any signs of night terrors. They may also carry out tests to look for other possible factors, which may be physical or psychological.
A sleep study may be recommended.
A sleep study, or polysomnography, involves spending the night in a sleep laboratory and having various measurements taken while sleeping.
Brain waves, blood oxygen levels, heart rate, breathing, and eye and leg movements are measured throughout the night, and the patient is filmed.
The doctor will review the recording and assess different aspects of the individual's sleep behavior.
The film may reveal irregular breathing, possibly suggesting apnea, or other reasons for a disturbed sleep, such as restless leg syndrome.
Medication is not usually needed for night terrors.
Although the night terrors appear distressing for children, any permanent harm is unlikely, and they usually pass without intervention.
Holding the child's hand and speaking calmly can help shorten an episode.
Treatment is normally necessary only if the episodes are having a significant negative effect on the safety of the person or their family, or if the problem is affecting their ability to function during the day.
If treatment is necessary, three types of intervention are possible.
- Treating an underlying condition: This could be sleep apnea or a mental health problem.
- Improving sleeping conditions: If sleep deprivation is a factor, changing sleeping habits or the sleep environment may help.
- Medication: Drugs are rarely used, but benzodiazepines and serotonin re-uptake inhibitors (SSRIs) may help in some cases.
- Dealing with stress: Therapy or counseling can help if stress seems to be a factor.
Home remedies and simple solutions
A number of simple interventions may help relieve night terrors.
- Safe sleeping environment: Close and lock all doors and windows at night. Consider alarming them. Remove trip hazards and remove fragile and dangerous objects.
- Stress: Identify any sources of stress and ways to relieve them. If a child is experiencing night terrors, ask them to tell you about anything that is bothering them and talk it through.
- Get more sleep: Sleep deprivation can be a factor, so try going to bed earlier or fitting in an afternoon nap. Having a relaxing routine before bedtime can also help, for example, a warm bath or light reading before sleep. Avoid screen time for at least an hour before going to bed.
- Look for patterns: Keep a sleep diary, and note how often the terrors occur and what time they begin. If the night terrors are bothersome, and they come at a regular time, one suggestion is to wake your child 15 minutes before they are likely to occur, keep them awake for 5 minutes and then let them go back to sleep.
Night terrors in adults
Night terrors are most common in children, but they can affect adults too. An adult can have night terrors at any time during the sleep cycle, and they are more likely to remember the dream than children are.
Adults are more likely to have night terrors if they have a history of:
Sometimes, night terrors can lead to injury for the person or other people, especially if they thrash about or go sleepwalking as well. An adult is more likely to display aggressive behavior than a child during night terrors.
Adults can also become embarrassed about their sleep behavior, and this can affect relationships.
Anyone who is concerned about night terrors might consider seeing a sleep specialist.