PARENTS/ GETTY IMAGES Key Takeaways Night terrors are episodes of screaming, crying, or thrashing that usually occur two to three hours after falling asleep during a stage known as non-rapid eye movement or deep sleep. Night terrors are caused by genetics, obstructive sleep apnea, acid reflux, or sleep schedule irregularities. If your child experiences night terrors, do not wake them up—keep them safe by removing sharp objects and keeping them away from stairs or obstacles.