Night terrors (or sleep terrors) differ substantially from standard nightmares and can be incredibly distressing for the sufferer and their family.
Although night terrors can be genuinely terrifying, they are not normally an indicator of anything more serious and tend to cease of their own accord.
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Here are some key points about night terrors. More detail and supporting information is in the main article.
- Night terrors are most common in children but can begin at any age.
- Night terrors typically stop without medical intervention.
- Research shows that there may be a genetic component to night terrors.
- An estimated 7 million people in the US have experienced night terrors at some point in their lives.
- 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?
Millions of people of all ages experience night terrors at some point in their life.
Night terrors are nocturnal episodes where the sufferer experiences terror. They may flail their limbs and scream and shout, and bouts are also often associated with sleepwalking.
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 can be substantially longer.1
Night terrors are unpleasant for all involved, but in general they are not a cause for medical concern.
A study conducted in Norway looking at various parasomnias (a category of sleep disorders) asked 1,000 randomly selected participants if they had experienced night terrors. The results showed that 10.4% of respondents had experienced night terrors at one point in their lives and 2.7% in the last 3 months.2
A similar study was conducted in the UK. Of the 4,972 participants, 2.2% reported having experienced night terrors.3
Extrapolating from these figures, we can estimate that more than 7 million people in the US will have experienced night terrors at some point in their lives.
Symptoms of night terrors
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.4
The signs of a night terror episode can include the following symptoms:
- 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
- Difficulty rousing from sleep
- Confusion on waking
- Staring wide-eyed (as if awake), but not responding to stimuli
- Aggressive behavior (more common in adults)
- Amnesia of the event (sometimes only partial).
Causes of night terrors
There can be a number of potential causes or contributing factors where night terrors are concerned. Below is a short list of some of the most common:
- Fever (in children, specifically)
- Sleep deprivation
- Light or noise
- An overfull bladder
- Spending the night somewhere unfamiliar
- A possible genetic component.
In a study of almost 7,000 children aged 8-10, with a follow-up around age 13, those children who were bullied were more than twice as likely to experience night terrors (an odds ratio of 2.01).14
Alongside these contributing factors, 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.
In one study, night terrors were associated with niacin deficiency in adults.16
A 2014 study that assessed 1,447 randomly selected patients with Parkinson's disease, aged 43-89 years, reported that 3.9% had night terrors (17.2% had nightmares and 1.8% experienced sleepwalking).15
In rare cases, the thalamus - located in the forebrain - may play a role in night terrors.
Research into parasomnias is ongoing, and slowly but surely our understanding of sleep and sleep disorders is deepening. The following factors may also play a part in some people's night terrors.
Connection to sleepwalking
It has been noted that night terrors and sleepwalking often go hand in hand. Both phenomena occur during slow-wave sleep (the deepest sleep stages) in the early part of the night.
Some researchers believe that patients who exhibit sleepwalking or night terrors may have an inherent difficulty in maintaining slow-wave sleep, making them susceptible to quick arousals where parasomnias can take hold.5
Although brain lesions are very unlikely to be the cause of night terrors, damage to or dysfunction of the thalamus does appear to be a significant factor in some cases.
In one study, a woman began having regular night terrors at the age of 48:
"She suddenly sat up in bed, screamed and appeared to be very frightened." 6
She underwent observation in a sleep laboratory to investigate their cause. The tests showed an increased signal coming from the thalamus which appeared to cause the micro-arousals suggestive of night terrors. 7
The thalamus is thought to play a pivotal role in the maintenance of sleep-wake cycles. It also acts as a dampener of the signals that normally arrive from the senses while we sleep.
Most of the information our brain receives from the outside world is passed through the thalamus before it is sent out to, for instance, the visual or auditory parts of the brain. During sleep, the thalamus is less inclined to send this information to the rest of the brain.
This dampening means that when we are asleep, we are much less aware of tactile stimuli and the sounds around us. 8
If you are an individual who suffers from night terrors or sleepwalking, you may already be aware that there seems to be some genetic component to these types of parasomnias.
A study that investigated parasomnias within families found that 80% of sleepwalkers and 96% of night terror sufferers had at least one other close family member affected by night terrors, sleepwalking or both conditions.9
Another investigation that focused on monozygotic (identical) and dizygotic (non-identical) twins also strongly supported the heritability of sleep terrors. The researchers found that a person is significantly more likely to experience night terrors if their identical twin suffers night terrors, whereas the likelihood is lower in non-identical twins.10
One study found that children with parents with a history of sleepwalking were more likely to have night terrors and more likely to have those night terrors be persistent. The peak time for night terrors to occur in childhood was 18 months of age, with 34.4% of children reported by parents to have night terrors, and up to a third of children who experienced night terrors going on to develop sleepwalking later in childhood.13
Tests and diagnosis of night terrors
Sometimes a sleep study is required to investigate potential causes of the night terrors.
Because of the nature of night terrors, doctors can often reach a diagnosis by asking the patient relevant questions.
Aside from questioning, a doctor may carry out further tests to investigate potential contributing factors, including physical and psychological components.
If a satisfactory conclusion cannot be reached, a sleep study could be recommended.
Sleep studies (polysomnography)
A sleep study involves spending the night in a sleep laboratory and having various measurements taken while sleeping.
Brain waves, blood oxygen levels, heart rate and breathing, as well as eye and leg movements, are measured throughout the night.
The patient will be filmed for the duration of the sleep study. The doctor will review the footage, assessing various aspects of the patient's sleep behavior. The video may show up irregular breathing, pointing toward some kind of apnea, or other reasons for a disturbed sleep, like restless leg syndrome.
Treatments for night terrors
There is rarely a need for any medication for night terrors. With children, although it appears distressing, it does not permanently harm them, and most children grow out of night terrors.
Gently restraining your child and speaking calmly can help shorten the episodes.
Treatment is typically only called upon if the episodes are having a significant negative effect on the sufferer or their family's safety, or their ability to function during the day. If treatment is deemed necessary, there are normally three categories of potential intervention:
- Treating an underlying condition: such as sleep apnea or a mental health problem
- Improving sleeping conditions: if sleep deprivation is thought to be a major factor
- Medication: drugs are rarely used, but benzodiazepines and serotonin re-uptake inhibitors have found to be useful in some cases11
- Dealing with stress: therapy or counseling can help if stress seems to be a factor.
In one study involving 45 children (aged 3-11) with night terrors, 31 were randomly selected to be treated for 20 days with L -5-hydroxytryptophan (L -5-HTP) at a dose of 2 mg per kg of bodyweight. After a month, 93.5% of patients had a positive response to treatment, while only 28.6% of children not receiving treatment had resolution of the night terrors.
After six months, 83.9% of those treated with L-5HTP were free of night terrors; 71.4% of the control group continued to experience night terrors.12
Home remedies and simple solutionsIf you or your child are suffering from night terrors, there are a number of simple interventions you can try. These methods may help minimize the terrors or at least lessen their impact:
- Make the sleeping environment safe: close and lock all doors and windows at night. Consider alarming them. Remove trip hazards and remove fragile and dangerous objects
- Stress: identify what makes you stressed and try to think of ways to alleviate it. If your 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 in this regard - a warm bath or light reading prior to sleep are often recommended (avoid screen time for at least an hour before going to bed)
- Look for patterns: keep a sleep diary. Note what time the night terrors begin. If the terrors come at a regular time, try to wake your child 15 minutes before they are due to occur, keep them awake for 5 minutes and then let them go back to sleep. This method has been found to be very effective but can, understandably, be difficult to implement.
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