We have other opposite problems with circadian rhythms that can happen when you - a lot of times with older adults. They start to go to bed at 6:00, 7:00 at night and they wake up at 2:00 in the morning. And they're rhythms actually shift earlier, but sometime it can just kind of miss the mark and shift too much earlier and that's when we need to treat it with bright light.

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.

Some patients are still having insomnia, but it's seems worse to them than actually it is. So, if they say they're sleep deprived, they haven't slept at all in three days; if we actually take them into a lab, most of the time we actually do see they're sleeping on and off here and there.

If there's a lot of fear that's going on, if there's a lot of anxiety, it's manifesting itself in your nocturnal world so that analyzing it can help open up basically thoughts about what you need to do during the day. So a lot of people who subscribe to the psychoanalysis, the Jungian thought will really focus a lot on dreams, the meaning, and how it can be used to help you during the day.

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.

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

So, it's not every patient that I see, but I'd say a good 70% to 80% of the patients when they go to bed it's like a stereo is playing at an 11 or 12 and they can't turn it down, at all. So it makes it very hard for their body to down regulate to be able to go to bed at night.