The measurement of change in sleep during depression and remission.

Sleep disturbances, which are a prominent symptom of depressive illness, were analyzed in endogenously depressed patients during depression and during full remission. These disturbances may be described at the level of sleep stages, at the level of the sleep profile, and at the level of consecutive sleep records. The scoring of sleep stages in sleep records of depressive patients provides difficulties, because the temporal coherence of different electrophysiological descriptors of sleep is weakened during depression. The sleep profile of depressed patients is characterized by alterations in the normal sequence of sleep stages and frequent stage changes. The disturbances in the sleep profile are unstable in that they show marked day to day fluctuations. It could be shown in some patients that there is a correlation between parameters of the first REM sleep and urinary free cortisol excretion in corresponding nights.