[Sleep and wake-cycle as circadian rhythm (author's transl)].

Sleep-wake cycles are closely tied with the circadian period of other bodily functions. Optimal synchronization is essential for troublefree alterations of sleep and wake periods. The neurophysiologic control areas are in various of the brain are far apart from each other for which reason a great variety of possible causes for sleep difficulties do exist. It has been shown recently that spezific mono-aminergic and cholinergic systems in the brain stem do control sleep. A case study will show that it is possible to improve sleeping difficulties with the serotonin precursor L-Troyptophan.