They woke up screaming and won't remember it in the morning

Telling them apart in the moment

Timing is the quickest tell. Night terrors happen in the deepest stage of sleep, usually early in the night — often before you have gone to bed yourself. Nightmares come in the second half of the night, when dreaming is most intense.

The child's state is the other tell. In a night terror they may scream, sit up, thrash, and look straight at you — and they are not awake. They cannot respond because there is nobody there to respond. A nightmare wakes them properly; they know you are there, and they want you.

Memory settles it by morning. A night terror is gone — they will have no idea it happened. A nightmare gets remembered, sometimes for weeks, and can start turning bedtime into something they dread.

Which means the distress is distributed unevenly, and not the way it looks. A night terror is frightening for you and, in a real sense, costs the child nothing — they were asleep throughout. A nightmare is mild to watch and lands entirely on them.

What to do with a night terror

Do not wake them. This is the one that matters. Waking a child mid-terror produces a confused, frightened child who now has something to remember — you have converted a non-event into a bad one.

Stay, stay calm, and keep them safe. Make sure they cannot fall or hit anything, gently steer them back if they try to get out of bed, and wait. Most children drop straight back into sleep afterwards, because they never surfaced.

Do not discuss it in the morning. There is nothing to discuss — they were not there — and describing it can create a fear of sleep that the terror itself never caused.

Tell anyone else who puts them to bed what these are and what to do. A babysitter or grandparent meeting one unbriefed will almost always try to wake the child, which is the single thing to avoid.

What to do with a nightmare

Go quickly, and comfort. This is the case where reassurance is genuinely the treatment — the opposite of the terror.

Do not debate whether the monster exists. You will lose, and arguing implies the question is open. "There is nothing here that can hurt you, and I am nearby" closes it better than proof does.

Equally, do not stage a rescue. Monster spray and checking the wardrobe confirm that the room needed clearing, which is the opposite of the message you meant to send.

Give them something to do about it in daylight rather than something to believe. Telling the story back, drawing it and tearing it up, a torch they control. Agency helps where argument does not.

When to raise it

Occasional night terrors in a toddler or preschooler, with no daytime consequences, are common and need nothing but a calm adult and a closed stair gate.

Worth raising with your pediatrician: terrors most nights rather than occasionally; anything involving breathing — snoring most nights, gasping, pauses; or a child who is exhausted during the day despite adequate hours in bed. Disrupted sleep and bad dreams often share a cause that is worth finding.

For nightmares, the line is the same as for any childhood fear: what matters is whether it is stopping them doing things. A fear that prevents sleeping, eating or leaving the house, or one still escalating after a couple of months, is a conversation rather than a phase.