Adolescence is a time of great susceptibility to sleep problems. A three-part approach to the assessment of sleeping and waking behavior in adolescents is planned with the following goals: to assess the mcehanisms of sleep function and the role of nocturnal sleep in achieving optimal alertness in adolescents; to evaluate the impact of daytime sleepiness on education and to investigate the efficacy of intervention; to achieve an estimate of the prevalence of specific sleep disorders in adolescents and to evaluate therapeutic interventions, as well as to begin the search for a biochemical marker of narcolepsy in adolescents "at risk" for the disorder. Mechanisms of sleep function and the role of nocturnal sleep in adolescents will be assessed in a number of sleep laboratory studies. These studies include an evaluation of the role of slow wave sleep in young and older adolescents, assessment of the relevance of sleep continuity, the effects of sleep length, napping, and the role of circadian rhythms. Educational impact will be determined from survey data and primarily from remote video observational studies in the classroom. In addition, one experiment is designed to assess the effectiveness of an educational program in junior high school students. The final series of project will include polysomnographic verification of sleep complaints, nonpharmacologic treatment of specific sleep disorders, and a longitudinal assessment of children "at risk" to develop narcolepsy.