Contribution of sleep physiology to depressive pathophysiology

Among the best characterized neurobiological changes in mood disorders are specific alterations in electroencephalographic (EEG) sleep, including disi nhibited rapid eye movement (REM) sleep and suppressed slow wave sleep. A s trong link between mood disorders and sleep is that depressive symptoms are alleviated by one night of sleep deprivation and reoccur after sleeping. S leep underlies homeostatic and circadian mechanisms that interact in comple x ways. These relationships have been formalized in electrophysiological, n eurochemical and neuroendocrinological models that extend to the pathophysi ology of affective illness, Sleep research as a pathophysiological window t o the brain has contributed extensively to the understanding of the neurobi ology of depression and has been a substantial guide for the advancement of model-driven clinical and preclinical research. Pharmacological probes of normal and depressed sleep play an important role. It is anticipated that t he combination of novel topographical EEG and neuroimaging techniques with traditional experimental methods will provide us with further insight into the neurobiology of sleep and depression. (C) 2001 American College of Neur opsychopharmacology. Published by Elsevier Science Inc.