Maybe your teeth have fallen out, you’ve been chased, or found yourself naked in public. If you’ve woken in a panic from any of these confusing, yet terrifying, scenarios—or something similar—you’ve had a nightmare. “They usually have some sort of violent or fearful content that will wake you up,” explains Michael J. Breus, PhD, founder of The Sleep Doctor. While nightmares happen in the last third of a sleep cycle and are typically remembered the following day, the same can’t be said for a night terror (also known as a sleep terror).

“Night terrors are more frequent in children, and will see them appear to wake up, scream, and scare the hell out of their parents, before calmly going back to sleep,” says Dr. Breus. A person experiencing a night terror may also thrash about or even jump out of bed. “It usually happens in the first third of the night during slow-wave sleep, and they will usually have almost no memory of the event the next day,” he adds.

Because of their timing, night terrors are clinically referred to as Non-rapid eye movement (NREM) sleep parasomnias (or NREM parasomnias). Night terrors are most common in children between the ages of 3 and 7. But they can happen at any age, and one to two percent of adults experience them.

What causes a night terror, and who’s more prone to them?

It is still unknown why night terrors happen, but researchers believe there’s a connection between the transition from light to deep sleep. There are also strong links to genetics and other parasomnias like sleepwalking. Additionally, the conditions below can increase your chances of experiencing night terrors:

• Sleep apnea
• Migraines
• A fever (especially in children)
• Stress
• Sleep deprivation
• A head injury
• Restless leg syndrome
• Too much caffeine
• Certain medications.

What to do if you or someone you know is experiencing night terrors

Getting more sleep is the first step. “Night terrors occur more often when you are sleep deprived,” explains Dr. Breus, advising to also “avoid alcohol, caffeine, and cannabis as they cause fragmented sleep, which can increase the likelihood of events.”

If it’s someone else experiencing night terrors, there are some other steps you can take to aid them. Firstly, the cardinal rule, like with sleepwalkers, do not wake them up. “You should not try to wake someone from a night terror, regardless of their age, as it can upset them further,” says Dr. Breus. “Rather, ensure that their bedroom is safe and that they cannot injure themselves if they leap out of bed.”

While you shouldn’t wake them during the fact, waking them beforehand may help avoid the terror altogether. “About 30 to 35 minutes after they’ve gone to sleep, go in and wake them up, and ask them three questions that require a response that is not yes or no.” For example: What’s the day today? What did you have for dinner? What’s your favorite book? “After that, let them go back to sleep,” says Dr. Breus. Alternatively, if you’re able to pinpoint the exact time the night terror continues to happen, wake them 30 to 35 minutes before that time and follow the same steps.