Among all the usual ills and problems adolescents face at school, you can add a new one—lack of sleep. Over the last several years, psychiatry professor Mary Carskadon, who directs chronobiology and sleep research at Bradley Hospital, has been on a crusade to up teenagers' snooze time. 

CARSKADON That's one of the toughest questions to answer because there's not a single number that really suits everyone, but the data seem to suggest on average, kids from middle school through high school will do best if they're getting a little more than nine hours of sleep a night.

BAM Wow, that's a lot.

CARSKADON Yes, it's a really tough sell for both students and parents, especially as you move into high school. For teens, it's a catch-22. Their biology is both pushing for and permitting them to stay awake later and that makes it harder to go to sleep earlier, but then the school districts are starting school earlier, so even if they are trying to get enough sleep, it's a challenge.

BAM So what's your advice?

CARSKADON Families need to look for a balance, because very often the children's sleep gets so pushed out of the picture that they hit a tipping point and become anti-social or depressed or develop a mood disorder, which nobody wants to see. It's just that, at some point, pushing too hard is counterproductive. The kinds of balances families need to look for have to leave sleep in the picture. 

Illustration by Timothy Cook