Parents have long known that the sleep-wake cycles of their
adolescent offspring are rather different to those of anyone
else in the household. Several new and detailed studies of
teenagers tell us why teens are impossible to awaken at 7 am,
suddenly awake at 10 pm, and often able to sleep anywhere for
stretches of 16 hours. Many parents know the scene: The groggy,
sleep-deprived teenager stumbles through breakfast and falls
asleep over afternoon homework, only to spring to life, wide-
eyed and alert, at 10 p.m.—just as Mom and Dad are nodding off.
Fortunately for parents, science has gotten more sophisticated
at explaining why, starting at puberty, a teen’s internal sleep-
wake clock seems to go off the rails. Researchers are also
connecting the dots between the resulting sleep loss and
behavior long chalked up to just “being a teenager.” This
includes more risk-taking, less self-control, a drop in school
performance and a rise in the incidence of depression. One 2010
study from the University of British Colum