So, sleep deprivation, and sometimes an insomnia, which is a little bit of a different form, but just getting a lack of sleep, can lead to a number of different decrements.

There's confusional arousals, there are states in deeper sleep that can happen where people will go and they'll disappear and they'll take on some other persona. They'll commit some crime, but it's all when they are in a very deep stage of sleep. So you really need to have a very thorough evaluation.

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, a nightmare just really has to evoke some sort of, we call it, dysphoric emotion or something uncomfortable. You could be sad, you could be unhappy; you could be scared, anxious. But traditionally, the definition is you have to awaken from this nightmare.

There are some that are - REM Behavior Disorder, we'll see some court documented cases. And they really need to have a thorough evaluation with a sleep specialist.

So the older models, when you look at Freudian, when you look at Jungian thought, and there's still people who really - who really use the Jungian thought of dream analysis, is really that you would analyze the dreams. The dreams are there for a purpose.

So when you're in REM sleep, your brain is very active, our body is quiet, but your brain is really processing a lot of things, a lot of emotions; we dream the most in REM sleep. And then you go back down in the deep stages, and so on and so forth.