Adolescence is a developmental period of accelerating physical,
psychological, social! cultural, and cognitive development, often
characterized by confronting and surmounting a myriad of challenges and
establishing a sense of self-identity and autonomy. It is also,
unfortunately, a period fraught with many threats to the health and
well-being of adoles- cents and with substantial consequent impairment
and disability. Many of the adverse health consequences experienced by
adolescents are, to a large extent, the result of their risk behaviors.
Many adolescents today, and perhaps an increasing number in the future,
are at risk for death, disease, and other adverse health outcomes that
are not primarily biomedical in origin. In general, there has been a
marked change in the causes of morbidity and mortality among
adolescents. Previously, infectious diseases accounted for a dispro-
portionate share of adolescent morbidity and mortality. At present,
however, the over- whelming toll of adolescent morbidity and mortality
is the result of lifestyle practices.