Not a method to use too often, of course.
I'm very curious about this, because I know that if I don't have something regularly scheduled for morning or early afternoon I tend to sink into depression, and now I'm wondering if I could perhaps be getting too much sleep. I had thought it was either a) getting sleep at the wrong times (I'll tend to stay awake later each night) and thus missing out on sunlight, or b) that regularity itself prevented my depression. This would also explain it, though.
The best way I can describe the effect is that for me it's like hitting a "reset" button in my brain. At first there's the tiredness and irritability that always go with not sleeping, but eventually I get a "second wind" and I feel normal, calm, and content. This generally lasts the whole rest of the day, until I fall asleep again.
The sleep deprivation treatment for depression used by some doctors in the '70s involved either total deprivation or waking the patients up around midnight, so that they slept only a few hours. I think I read that both worked equally well, but I have only tried the former. And as far as I know, nobody has figured out why it works for so many people.
It was peculiar to note that people who are short-sleepers also share a slight manic trait in their personality. While the article makes short-sleep cycles out to look like all sunshine and roses it is not all it is cracked up to be. I get between 2 and 4 hours sleep a night and on a good night I get 6. I have to monitor the sleep I am getting because if I allow myself to fall into a cycle of 2 hours for an extended time I start to have problems with my heart and abnormal rhythms. If the > 4 hours cycle goes on for more than a week I have to start taking medicine to sleep to ensure that my body is receiving an adequate amount of sleep. I see no negative effects if I get 4-6 a night, but it is probably safe to assume that short-sleep cycles rides the line between good and bad health. I never considered myself a short sleeper I just figured I have insomnia but never worried too much about it because I feel no different if I get 4 or 8 hours of sleep a night (if I can get 8) and the fact that my father and grandfather shares the trait and are healthy (grandfather is almost 90) . On the plus side, I experience more life and get more done which are really the only benefits to sleeping less.