A night terror is a brief disruption of normal sleep in which the sleeper becomes terrified; it is like a nightmare but much worse. Afterwards, the sleeper usually returns to normal sleep without regaining consciousness.

Night terrors, also known as sleep terrors and pavor nocturnes, tend to last between one and six minutes and are most common in children. Although distressing to those who witness them, the attacks are mostly harmless and most children grow out of them.

Night terror or nightmare?

There are six major differences between a night terror and a nightmare:

  1. Place in the sleep cycle: night terrors occur during the part of the sleep cycle not associated with dreaming whereas nightmares usually happen during dreams.
  2. Amnesia: people who have night terrors don’t usually remember them.
  3. Confusion: people who wake up just after a night terror are confused and disoriented.
  4. Rousing: it is difficult to wake people from night terrors; it is relatively easy to wake someone from a dream, nightmare or otherwise.
  5. Fearful behaviour: people having a night terror appear terrified; people having a nightmare show less intense fear.
  6. Timing: night terrors tend to occur during the first three hours of sleep; nightmares tend to occur in the last hour of sleep.

Night terrors, dreaming and the sleep cycle

The sleep cycle comprises two main stages; rapid eye movement (REM) sleep and non-REM (NREM) sleep. Dreaming is mostly associated with REM sleep but night terrors usually occur during NREM sleep. While nightmares are ‘normal’ dreams because they occur during REM sleep, night terrors are ‘non-normal dreams’.

Each sleep cycle lasts 90–100 minutes, so most people pass through five or so cycles every night. Most night terrors occur during the first sleep cycle. It is rare to have two or more attacks in a single night.

What happens during a night terror?

Night terrors affect your behaviour and the way you feel:

  • Behavioural signs: these tend to start with vocalisation, including screaming and sleep-talking. The person affected can become agitated, with thrashing, flailing limbs, or even sleepwalking away from their bed to ‘escape’.
  • Physiological signs: these are those associated with the body’s reaction to trauma: increased heart rate, sweating, rapid breathing, dilated pupils and shaking. These physiological signs can be extreme; heart rate, for instance, often doubles.

The dreams experienced by people having a night terror are terrifying – falling off cliffs, being violently assaulted, being deserted and vulnerable, for instance. The person experiencing an attack usually cannot be comforted or reassured, which is particularly hard for parents whose child is prone to night terrors.

What causes night terrors?

Overall, about one-third of people experience an isolated night terror during their lifetime. Children of three to seven years old are most prone to repeated night terrors with about 2% experiencing attacks frequently. Incidence generally declines with age and few teenagers experience regular night terrors. Only in rare cases do people develop night terrors late in life.

It is thought that having night terrors might be a normal part of growing up, in that the brains of children are immature and need time to develop normal sleep patterns. Genetics may also be a factor, in that incidence seems to run in families. Beyond this, sleep deprivation or erratic sleeping habits seem to make night terrors more likely.

In some people, emotional disturbance triggers a night terror. Adults with post-traumatic stress disorder, for example, can be affected. Other factors associated with attacks include symptoms associated with depression, low self-esteem, anxiety, difficulty in expressing aggression and phobias. Use of some medications, including antihistamines, tricyclic anti-depressants, anti-psychotic drugs and alcohol abuse can trigger night terrors.

Night terrors and other disorders

Night terrors can be misdiagnosed and they can also occur with other disorders.

  • Misdiagnosis: other than with nightmares, night terrors may be confused with epilepsy, nocturnal panic attacks and sundowning syndrome. Nocturnal panic attacks are easily remembered and do not, in general, lead to confusion. Sundowning syndrome, in which people start showing very odd behaviour during the evening or early part of the night, is common in people with dementia. People with sundowning syndrome are conscious during episodes of abnormal behaviour and do not usually appear ‘terrified’.
  • Co-occurring disorders: night terrors are mainly associated with other sleep disorders, particularly sleepwalking and sleep-talking. Each of these may occur independently of the night terror.

Coping with night terrors

Managing night terrors requires different techniques depending on whether a child or an older adult is affected:

  • Coping in children: during attacks, don’t try to wake the child; instead, provide comfort by speaking gently and calmly; walking the child by the hand if they are sleepwalking may also help. Reduce the risk of physical injury, by, for example, removing hard objects from the child’s bedroom before they go to sleep. If attacks tend to occur at a given time after falling asleep, wake the child slightly before an attack is due, provide comfort, and ease the child back to sleep. If you are worried, a visit to your GP may be needed.
  • Coping in adults: adult night terrors are more likely to require medication.

Your GP will first need to confirm that night terrors are the problem. He or she might refer you to a sleep clinic. These have the technology and expertise to monitor your sleep cycle, including its REM and NREM sleep and can identify the precise nature of a sleep disorder in children and in adults. Treatment can then involve medication and/or cognitive behaviour therapy.