Waking up startled and delirious every night

My wife wakes up startled and delirious every night. It seems to happen about 1 hour after falling asleep, regardless of the time she goes to sleep. She wakes up, usually yelling "Hey! Hey! Hey!"' and then she might run around turning on lights looking for our kids, or she might say something incoherent like "Where's the Boy?!" (we have two daughters). She doesn't come out of the "dream" for a while. If I respond forcefully (e.g., "It's just a dream! Go back to sleep!") then, it lasts longer. If I respond gently (e.g., put my arm around her, and say "Maybe you're just dreaming... try to lay down.") then she seems to be able to relax much quicker. It only happens once every night, but it happens almost every night. It seems that taking an ibuprofen before going to bed can stop it from happening. Anyone have any suggestions on what to do about this?