Sleep and sleepiness in children and adolescents.

We have attempted to review the current "state of the art" regarding the ontogenetic course of sleep-wake state organization and possible disruptions in this course from infancy through adolescence. It is becoming increasingly important for clinicians to learn about physiologic functioning during sleep. Much more research is required, directed at the relationship between waking behaviors and sleeping behaviors. Investigations of daytime sleepiness in adolescence, of the relationship of hyperactivity to excessive sleepiness, of the relationship between disorders such as depression and anorexia nervosa with disturbed sleep state organization, and of primary sleep disorders such as narcolepsy and the sleep apnea syndrome only scratch the surface in terms of the future work that needs to be done.