Abstract
The question as to whether the beneficial effect of sleep deprivation in depression is related to the increased wakefulness or to the sleep suppression by itself, is made moot by the search activity concept. According to this concept, rapid eye movement (REM) sleep is functionally deficient in depression and increases feelings of helplessness and hopelessness instead of restoring mood and search activity. Thus, REM sleep deprivation, either selective or not, is beneficial by breaking a vicious circle: depression in wakefulness…giving up (helplessness) in dream scenario…increased depression in the subsequent wakefulness. In addition, sleep deprivation is an important challenge for the depressed patient. The ability to confront this challenge and maintain wakefulness has a positive outcome on depression, especially when wakefulness is accompanied by active behavior.