The WSJ's Melinda Beck identified a new elite group, which may induce even more envy than billionaires or aristocrats: The Sleepless Elite.

These are the 1% to 3% of the population who live happily on just a few hours of sleep per night.

During the day they don't need caffeine, as they are energetic and upbeat. They tend to be thin, thanks to a fast metabolism, and they have a high tolerance for physical and psychological pain.

Now before you decide that you are a sleepless elite, psychiatrists give this warning:

Out of every 100 people who believe they only need five or six hours of sleep a night, only about five people really do, Dr. Buysse says. The rest end up chronically sleep deprived, part of the one-third of U.S. adults who get less than the recommended seven hours of sleep per night, according to a report last month by the Centers for Disease Control and Prevention.

To date, only a handful of small studies have looked at short sleepers—in part because they're hard to find. They rarely go to sleep clinics and don't think they have a disorder.

Benjamin Franklin, Thomas Jefferson and Leonardo da Vinci are suspected to be short sleepers. But not all short sleepers are highly successful.