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.

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.

Night terrors are in deep sleep, and they're more common in kids, as are nightmares, but what happens in a night terror is like a flash - we think a flash of some image or something happens in the brain. We don't really quite know what. And it usually ends up with the child screaming almost like screaming bloody murder. It's very scary for the parents or whoever else is around.

I'll work on patient's thoughts about sleep, "So I must get eight hours of sleep tonight or I won't sleep tomorrow." That sometimes - or "I won't function tomorrow." That sometimes makes it very difficult for you to sleep at night

There are other people that think that dreams actually do serve a purpose. But what that purpose is, we're not really sure. So some people believe that it actually does have some psychological representation of what's going on in the day, but there's no need to sit and really analyze it.

So someone who is a child usually goes to bed about 8:00 or 9:00 at night, but then when they have a circadian rhythm shift, it shifts later. And this is natural. And they start to go to bed at 11:00, 12:00, 1:00 and they want to sleep later. So we see this a lot in teens.

Now circadian rhythms become very interesting and problematic for patients because when you become a teenager, your rhythms actually tend to naturally shift.