When you're in the more deeper stages of sleep - REM sleep, your body is quiet, but your mind is actually very active. So it's a time when your body and your brain is restoring itself. It's repairing any cell damage that happened during the day, it's really repairing, like I said, repairing your body, but also helps with digestion, helps with memory.

We'll work on relaxation strategies and also changing the times you go to bed will actually make them sleep a little bit less for a few nights so their body's natural sleep drive starts to kick in. That is very effective in about 60% to 70% of patients who do it, four to eight sessions, not even every week; it works for 60% to 70% of patients.

And you cycle throughout so that you do about five to six cycles throughout the night. And we spend more time in REM later on in the night than we do earlier on.

Really if it's an hour or two after you've fallen asleep because you're in such a deep sleep at that point.

There are people who have repetitive nightmares. And what happens is their brain is trying to process the stress and help their brain actually deal with what happens if this stress happens again, so their brain's preparing them to deal with it in case the stress happens again, but it's so scary that they awaken from it.

There's some debate as to whether you need to awaken from them because there are some patients who are actually starting to say, "I had these horrible nightmares, but I never woke up from them." But they can still recall them when they get up in the morning. So there's still some debate in the field.

We think is happening in the brain, the way I like to think about it is, it's almost like, you're brain is going through all these stages of sleep and it's developing in children so fast that it's almost like you're shifting gears in a car. And at some point, you actually stall out a little bit, and that's kind of what happens during a night terror.