Night Terrors: How They Differ From Nightmares

Written and Reviewed by the Cognitive Train Team
← Sleep

A child can sit upright, scream, stare through you, and seem terrified—yet still be mostly asleep. By morning, the person who witnessed it may remember every second. The sleeper may remember nothing.

Night terrors, clinically called sleep terrors, are episodes of incomplete awakening from deep non-REM sleep. They can involve a sudden scream, intense fear, rapid breathing, sweating, a racing heart, and confused or forceful movement. Attempts to comfort the sleeper may receive little response because the brain has not fully reached wakefulness.

That is the central difference from a nightmare. A nightmare is a disturbing dream that usually ends in full awakening and can often be described afterward. A night terror is primarily a disorder of arousal: part of the brain wakes while other parts remain in deep sleep.

What Happens During a Night Terror?

Sleep terrors belong to the same family of NREM disorders of arousal as confusional arousals and sleepwalking. They most often emerge from stage N3, the deepest part of non-REM sleep, when the brain attempts to shift toward wakefulness but does not complete the transition.

A 2023 review of NREM parasomnias describes sleep terrors as abrupt fear arousals with strong autonomic activation, limited responsiveness, little or no dream imagery, and amnesia for the event. The eyes may be open, but open eyes do not mean full awareness.

How night terrors differ from nightmares Two stacked cards compare night terrors, which usually arise from deep non-REM sleep early in the night with incomplete awakening and little recall, with nightmares, which usually arise from REM sleep later in the night with full awakening and detailed dream recall. Fear can come from two different sleep states Timing, awareness, and recall separate them Night terror Sleep state: deep NREM sleep Timing: usually first part of the night Awareness: incomplete and confused Comforting: may not register Morning recall: little or none The body looks awake before the brain fully is. Nightmare Sleep state: usually REM sleep Timing: often later in the night Awareness: wakes fully Comforting: usually responsive Morning recall: dream may be detailed The frightening dream leads into wakefulness. Both are real— but they are not the same event.

What Does a Night Terror Look Like?

An episode may begin with a sudden scream or gasp. The sleeper may sit up, thrash, push someone away, run from the bed, or appear to defend against something unseen. Breathing and heart rate accelerate, the pupils may widen, and the skin may become sweaty or flushed.

The episode usually lasts seconds to several minutes, although it can feel much longer to a frightened witness. Speech may be limited or incoherent. When the episode ends, the sleeper often settles back into sleep and has little or no memory the next morning.

Not every event follows this exact script. Some are quieter, and a small amount of mental imagery can occasionally be recalled. The diagnosis depends on the overall pattern rather than one dramatic feature.

Night Terrors vs. Nightmares

The easiest distinction is what happens after the fear. Someone waking from a nightmare usually becomes alert, seeks comfort, and can describe a frightening story. Someone in a night terror may look awake but remain confused, resist comfort, and remember little later.

Timing helps too. Deep NREM sleep is concentrated early in the night, so sleep terrors usually occur during the first third or half. REM periods lengthen toward morning, making nightmares more common later. Timing is useful, not absolute; unusual patterns still require the full history.

Why Are Night Terrors Common in Children?

Sleep terrors are most common in childhood, when deep sleep is abundant and transitions between sleep states are still developing. A review focused on sleep terrors estimates that roughly 1% to 6.5% of children experience them, with most cases improving by adolescence.

They can persist into adulthood or begin later, but new adult-onset episodes deserve closer attention. Adult events may be influenced by sleep disruption, another sleep disorder, medication or substance effects, stress, trauma-related symptoms, or a condition that resembles a parasomnia.

What Can Trigger or Worsen an Episode?

A predisposed brain is more likely to have an incomplete arousal when deep sleep is intensified or repeatedly interrupted. Common contributors include sleep deprivation, irregular sleep, fever, stress, a noisy environment, alcohol in adults, and unfamiliar sleeping conditions.

Conditions that repeatedly provoke arousal can also matter. Obstructive sleep apnea, restless legs symptoms, and periodic limb movements may fragment sleep and trigger parasomnia episodes. Treating the disruption can reduce the events without treating the terror itself as a separate disease.

Do not assume that every episode proves psychological trauma. Stress can increase vulnerability, particularly in adults, but childhood sleep terrors commonly occur without a psychiatric cause.

What Should You Do During a Night Terror?

Stay calm and focus on preventing injury. Do not shake, shout at, or force the sleeper fully awake. Waking someone from a night terror is not dangerous, but aggressive attempts can increase confusion and resistance without ending the episode quickly.

  • Move hard or sharp objects out of reach.
  • Block access to stairs, windows, or exterior doors.
  • Speak quietly and use simple reassurance.
  • If the person leaves the bed, guide rather than restrain when possible.
  • Let the episode pass, then help the sleeper return to a safe bed.

Do not question a child about frightening dream details the next morning when no memory is present. The witness may be far more distressed than the sleeper.

When Is Testing Needed?

Typical childhood sleep terrors can often be identified from the history and do not automatically require a sleep study. Keep a record of bedtime, episode time, duration, behavior, illness, sleep loss, snoring, medication changes, and morning recall. A short home video can help a clinician understand the event.

Video-polysomnography or video-EEG becomes more useful when events are unusual, injurious, frequent throughout the night, highly stereotyped, newly appearing in adulthood, or difficult to distinguish from seizures, REM sleep behavior disorder, or breathing-related arousals. A video-EEG analysis of NREM parasomnias and nocturnal epilepsy shows why timing, repetition, behavior, and recorded brain activity may all be needed in difficult cases.

What Actually Helps?

For most children, reassurance, adequate sleep, a consistent schedule, and a safe bedroom are the main interventions. Reducing sleep deprivation matters because deeper rebound sleep can make incomplete arousals more likely.

When episodes occur at a predictable time and happen frequently, a clinician may suggest scheduled awakenings: gently waking the child shortly before the usual episode, keeping them awake briefly, and repeating the plan for several nights. A 2023 systematic review of behavioral treatments found scheduled awakenings among the most frequently reported approaches, but the evidence remains limited and many studies are small or uncontrolled.

Medication is rarely needed for ordinary childhood sleep terrors. Severe, dangerous, persistent, or functionally disruptive episodes require individual assessment rather than an over-the-counter sleep product or borrowed prescription.

The Frightening Part Belongs Mostly to the Witness

Night terrors look dramatic because the sleeper’s body activates before awareness fully returns. That is different from waking out of a remembered frightening dream. Timing, responsiveness, and recall usually reveal which pattern occurred.

Continue through the parasomnia guide, the broader sleep-disorders overview, or the Sleep section for other nighttime behaviors and sleep problems. The free brain tests collection measures waking attention, memory, and speed; it cannot identify a parasomnia. Cognitive Train’s wider brain training and cognitive testing library focuses on waking abilities rather than incomplete arousals from deep sleep.