Sleep and depression - results from psychobiological studies: an overview

Disturbances of sleep are typical for most depressed patients and belong to the core symptoms of the disorder. Polysomnographic sleep research has dem onstrated that besides disturbances of sleep continuity, in depression slee p is characterized by a reduction of slow wave sleep and a disinhibition of REM sleep, with a shortening of REM latency, a prolongation of the first R EM period and increased REM density. These findings have stimulated many sl eep studies in depressive patients and patients with other psychiatric diso rders. In the meantime, several theoretical models, originating from basic research, have been developed to explain sleep abnormalities of depression, like the two-process-model of sleep and sleep regulation, the GRF/CRF imba lance model and the reciprocal interaction model of non-REM and REM sleep r egulation. Interestingly, most of the effective antidepressant agents suppr ess REM sleep. Furthermore, manipulations of the sleep-wake cycle, like sle ep deprivation or a phase advance of the sleep period, alleviate depressive symptoms. These data indicate a strong bi-directional relationship between sleep, sleep alterations and depression. (C) 2001 Elsevier Science BN. All rights reserved.