What is the name of the mental illness characterized by the belief that one is dead?

Cotard's syndrome, also known as Cotard's delusion or nihilistic delusion, is a rare mental illness characterized by the belief that one is dead, does not exist, or has lost their internal organs or blood. Individuals with this condition may present with various degrees of depression, anxiety, and disconnection from reality, leading to extreme beliefs about their existence and overall well-being.

The hallmark of Cotard's syndrome is the profound delusion regarding one’s own mortality, which can result in significant social withdrawal, neglect of personal care, and even suicidal ideation. This syndrome often poses unique treatment challenges due to the nature of the delusions affecting the person’s ability to engage in traditional therapeutic interventions.

In contrast, the other conditions listed, such as Rett syndrome, which primarily affects females and leads to severe cognitive and physical impairments, Ekbom's syndrome (also known as delusional parasitosis, where the individual believes they are infested with parasites), and Tourette's syndrome (characterized by motor and vocal tics), do not involve such delusions about one's own death or existence. Thus, they do not align with the specific features of Cotard's syndrome.