Night terrors are dramatic and frightening to watch in children but, in most cases, they are not harmful and can be managed in a straightforward way without the need for medication or complex medical tests.

What are night terrors?

Night terrors are part of a group of "disorders" called parasomnias, which are undesirable movements or behaviours occurring during sleep. They include sleep terrors, sleep-walking and states of confusion or arousal, all of which overlap and are part of a spectrum of problems.

If your child has night terrors, these are likely to be characterised by facial expressions of extreme fear, associated with screaming, shouting and agitation. The child is seemingly awake but does not recognise or respond to the people around them. In fact, they often push their parents away or try to run from them, which is very distressing for the parent. Older children may even leap out of bed and run around blindly trying to get away from some unseen danger.

During night terrors the child may have a racing pulse, sweaty skin, dilated pupils, quivering movements and rapid breathing, all of which are associated with a marked activation of the child's autonomic (involuntary) nervous system.

An episode of night terror is usually brief, lasting around one to five minutes, although some can last up to half-an-hour.

Night terrors occur when the child is partially aroused from deep, restful sleep [non-rapid eye movement (REM) sleep], so typically they occur within two hours of the child falling asleep. They usually cease abruptly, with the child returning to a deep sleep and not remembering anything the following morning.

Confusional arousal is similar

Confusional arousal is a similar sleep problem. It causes the child to be very confused, but it does not result in the very intense fear or autonomic nervous activation seen in true night terrors.

Confusional arousal is often thought of as a mild form of night terrors, and often little distinction is made between the two.

Which children are likely to get night terrors?

Night terrors in their severe form tend to affect slightly older children, with a peak between five and seven years of age. They may affect up to three in 100 children of this age.

A milder form can occur in toddlers and preschool children, and these are probably more frequent, affecting up to 15 in 100 preschoolers and toddlers.

There seems to be a probable genetic predisposition for night terrors. A child has a 10-times higher risk of night terrors if a first-degree relative (mother, father, brother, sister) had them, and there is an additional 60% increased chance of a child being affected if both parents had them when young.

Night terrors also occur together with other sleep disorders such as restless legs, teeth grinding, sleep talking, sleep walking, sleep-disordered breathing and nightmares. There does not appear to be a bias towards girls or boys.

If your child is taking a medication - such as a sedative to aid sleep, a stimulant, an antihistamine or certain medications to control psychological conditions - these may trigger night terrors. Likewise, the acute stress of a fever or sleep deprivation may also increase the likelihood of an episode occurring.

Could it be something else?

If you think your child has night terrors and you take him or her to your doctor, the doctor might need to get a better insight into the symptoms and behaviours to exclude other possibilities, which can include the following problems.

Nightmares - these occur towards the end of a night's sleep (ie, one to two hours before waking rather than one to two hours after getting off to sleep). Also, the child is woken by the dream, can be comforted and will often remember the dream the next day.

Epileptic seizures - these can occasionally appear similar to night terrors, but they tend to be short-lived, with stereotypic movements and abnormal muscle tone. These seizures often occur in clusters throughout the night rather than as a single episode, and may be associated with daytime seizures or absence episodes (ie, "phasing out", not remembering what happened) as well.

Cluster headaches - these are more common in older children but can appear as a period of arousal followed by agitation and daytime headaches. A family history of headaches is commonly found.

The doctor will need to ask about sleep patterns and night-time routines as well as medication use (including over-the-counter pharmacy preparations), so keeping a detailed account of the episodes and related factors would be helpful for the diganosis.

Physically, the doctor may look to find features that may cause sleep disruption; eg, enlarged tonsils which may cause obstructive sleep apnoea (disrupted breathing), limb pain at night or stomach acid reflux.

Practical tips for parents

It is reassuring that the outlook for the child with night terrors is good. Most children grow out of them by late childhood or adolescence, and there are usually no long-term psychological effects.

A good bedtime routine is important, as is the need to keep the child safe if they do tend to sleepwalk. It is a good idea to lock outside doors and windows, have the child sleep in groundfloor room, and perhaps put them to bed in a sleeping bag for some restraint.

Night terrors tend to occur at about the same time each night, so it may help to wake the child with a gentle nudge about 15 minutes before that time and then let them drift off to sleep again. Often, after four or five nights, this can effectively stop the terrors.

Medications are recommended by doctors in some more severe cases (eg, some antidepressant and anticonvulsant drugs), but these children really need a full assessment and investigation before such treatments are tried.

A child might need need further assessment or investigations if: 

• there is history or any evidence or clinical suspicion of sleep apnoea (disrupted sleep breathing) 
• episodes are unusual or have stereotypic features suggestive of seizures 
• there are daytime seizure-like episodes 
• the child is unusually sleepy the day afterwards 
• episodes are occurring at an unusual age (in very young or older childhood with no previous sleep disturbances) 
• episodes are frequent, severe, prolonged, dangerous or disruptive.

This article was originally written by Dr Marguerite Dalton, a paediatrician based in south Auckland and the national coordinator of Well Child/Tamariki Ora Week www.wellchild.org.nz/. It was first published in New Zealand Doctor newspaper, July 2007. Edited by everybody, April 2008. Copyright UBM Medica (NZ) Ltd 2008.