Problem: When you and your spouse are up late watching a movie, your child walks down the steps, mumbles something about needing to make a sandwich, and starts rummaging around in her backpack.
Likely diagnosis: Sleepwalking and sleep talking. While night terrors affect just a small percentage of kids (the same deep-sleep trigger causes all three behaviors), half of kids will sleepwalk at some point during childhood, and almost all kids talk in their sleep.
In-the-moment fixes: If your child sleepwalks, you should gently guide her back into bed, trying not to wake her up so you don't unnecessarily disorient her. If she's talking in her sleep, ignore it.
Long-term solutions: Make sure your child gets enough sleep, perhaps by gradually introducing an earlier bedtime. When you're sleep-deprived, your body compensates by increasing the percentage of time spent in deep sleep, which is exclusively when night terrors occur, says Dr. Owens. The more sleep she gets, the less time she'll spend in deep sleep.
In the meantime, you'll also want to do some childproofing (or don't undo what you did when your child was a baby) such as installing stair and doorway gates so that any nighttime wandering that does occur is safer.