Night terrors and nightmares are both frightening sleep experiences, but they happen during different stages of sleep, look completely different from the outside, and are remembered very differently afterward. Understanding which one you or your child is experiencing changes how you respond to it.
When They Happen During Sleep
The most fundamental difference is the type of sleep involved. Nightmares occur during REM sleep, the stage when most vivid dreaming takes place. Because REM periods grow longer as the night progresses, nightmares are most common in the early morning hours, roughly the last third of the night.
Night terrors happen during deep non-REM sleep, which is concentrated in the first few hours after falling asleep. Episodes typically strike in the first half of the night, sometimes more than once, and can last up to 15 minutes. This distinction in sleep stage explains nearly every other difference between the two.
What Each One Looks and Feels Like
A nightmare is essentially a bad dream. The person experiencing it lies relatively still, may whimper or shift around, and then wakes up feeling scared or upset. They’re fully alert within moments and can usually describe what the dream was about. Heart rate may be elevated, but the physical response is modest.
A night terror is a dramatically different event, especially to witness. It often begins with a sudden, panicked scream. The person may sit bolt upright, thrash, sweat heavily, breathe rapidly, and have a pounding heart rate. Their eyes might be open, but they’re not truly awake. They appear terrified and are largely unresponsive to people around them. Trying to comfort or talk to someone mid-episode often doesn’t register, and attempting to wake them can make the agitation worse.
After a nightmare, you wake up and know exactly what happened. After a night terror, the person usually has little or no memory of the episode. They may settle back into quiet sleep on their own without ever fully waking. If they do wake, they’re confused and disoriented rather than recalling a scary story. This amnesia is one of the clearest ways to tell the two apart.
Who Gets Them
Nightmares are universal. Nearly everyone has them occasionally, and they’re especially common in children but persist throughout adulthood. Frequent nightmares that disrupt sleep quality can become a standalone sleep problem at any age.
Night terrors follow a narrower pattern. Children between ages 3 and 7 are most at risk, and most children outgrow them before reaching high school. By adolescence or early adulthood, episodes have typically stopped. Night terrors do occur in adults, but far less commonly, and adult-onset episodes are more likely to be linked to an underlying trigger.
Triggers and Risk Factors
Nightmare frequency tends to increase with stress, anxiety, traumatic experiences, certain medications, and irregular sleep schedules. In adults, frequent nightmares often overlap with mood disorders or post-traumatic stress.
Night terrors share some of those triggers but have a few distinct ones. A family history of night terrors or sleepwalking is one of the strongest risk factors, pointing to a genetic component. Other common triggers include:
- Sleep schedule disruptions: travel, changes in routine, or anything that fragments sleep
- Fever: particularly in children
- Sleep-disordered breathing: conditions like obstructive sleep apnea that interrupt normal sleep cycles
- Restless legs syndrome
- Mood disorders: depression and anxiety
- Alcohol use
The common thread among many of these triggers is that they interfere with the normal progression through sleep stages, making it more likely that the brain gets “stuck” during the transition out of deep sleep.
How to Respond to Each
Responding to a nightmare is straightforward. The person wakes up, knows they had a bad dream, and benefits from reassurance. With children, talking through the dream, offering comfort, and helping them settle back to sleep is usually enough. For adults with recurring nightmares, cognitive approaches that involve rehearsing a changed version of the dream during waking hours can reduce their frequency over time.
Responding to a night terror requires a very different approach. The most important thing is to not try to wake the person up. Shaking or shouting at them can escalate the agitation and confusion. Instead, stay nearby, speak in calm, soothing tones, and gently guide them back to bed if they’ve gotten up. The episode will pass on its own, usually within a few minutes.
Safety is the primary concern during a night terror. Because the person may move around, flail, or even walk, there’s a real risk of falling down stairs, running into furniture, or breaking something. For children with frequent episodes, making sure the sleep environment is safe (gates on stairs, sharp objects out of reach, windows secured) matters more than any intervention during the episode itself.
When Night Terrors Signal Something Else
Occasional night terrors in a young child with no other sleep problems are a normal part of development and rarely need medical evaluation. The picture changes if episodes are very frequent, continue past early adolescence, start for the first time in adulthood, or are accompanied by excessive daytime sleepiness. In those cases, an underlying sleep disorder like obstructive sleep apnea or restless legs syndrome may be driving the episodes. Treating the root cause often resolves the night terrors.
For nightmares, the threshold is similar. Occasional bad dreams are normal. Nightmares that happen multiple times a week, cause you to dread going to sleep, or significantly affect daytime functioning cross into a pattern that benefits from targeted treatment. Effective therapies exist for both conditions, and most people see significant improvement once the right approach is identified.