[Pathophysiology of sleep]

Disturbed sleep is a frequent concomitant of depression and of normal aging. Simultaneous investigations of sleep EEG and of nocturnal hormone secretion reveal that under both conditions slow-wave sleep and growth-hormone secretion decrease and sleep continuity is disturbed in comparison to younger normal controls. Animal studies and recent data from investigations in our laboratory in young and elderly normal controls and in patients with depression demonstrate that the neuropeptides growth hormone-releasing hormone (GHRH) and corticotropin-releasing hormone (CRH) are common regulators of peripheral hormone secretion and of sleep structure. We suggest that changes of the ratio between both peptides play a key role in the pathophysiology of sleep endocrine aberrations during aging and depression.