Abstract
Summary Out of 102 patients suffering from endogenous depression, it was possible to ascertain the duration of episodes in the case of 60 patients. Intraindividual comparisons among patients with unipolar depression show that sleep deprivation therapy causes a tendency to shorter depressive episodes. This tendency is related to the time of application of sleep deprivation: the sooner sleep deprivation is applied within an episode, the better the effect. Younger patients react better than older ones.