CIRCADIAN-RHYTHMS AND THE PHARMACOLOGY OF AFFECTIVE-ILLNESS

The chronic effects of antidepressant drugs (ADs) on circadian rhythms of behavior, physiology and endocrinology are reviewed. The timekeepi ng properties of several classes of ADs, including tricyclic antidepre ssants, selective serotonin reuptake inhibitors, monoamine oxidase inh ibitors, serotonin agonists and antagonists, benzodiazepines, and mela tonin are reviewed. Pharmacological effects on the circadian amplitude and phase, as well as effects on day-night measurements of motor acti vity, sleep-wake, body temperature (Tb), 3-methoxy-4-hydroxyphenylglyc ol, cortisol, thyroid hormone, prolactin, growth hormone and melatonin are examined. ADs often lower nocturnal Tb and affect tile homeostati c regulation of sleep. ADs often advance the timing and decrease the a mount of slow wave sleep, reduce rapid eye movement sleep and increase or decrease arousal. Together, AD effects on nocturnal Tb and sleep m ay be related to their therapeutic properties. ADs sometimes delay noc turnal cortisol timing and increase nocturnal melatonin, thyroid hormo ne and prolactin levels; these effects often vary with diagnosis, and clinical state. The effects of ADs on the coupling of the central circ adian pacemaker to photic and nonphotic zeitgebers are discussed. Copy right (C) 1996 Elsevier Science Inc.