Walking Corpse Syndrome: they believe to have died
It is a syndrome of mental depression and suicidal tendencies, in which the patient complains of having lost everything: possessions, part of or entire body, often believing that he or she has died and is a walking corpse. This delusion is usually expanded to the degree that the patient might claim that he can smell his own rotting flesh and feel worms crawling through his skin. The latter phenomenon is a recurring experience of people chronically deprived of sleep or suffering amphetamine/cocaine psychosis. Paradoxically, being "dead" often gives the patient the nation of being immortal.