It’s commonly described as the walking dead disease, but Cotard’s syndrome is broader than that.

New Scientist has interviewed a man who once believed that he was dead (he got better). The man had attempted to kill himself by electrocuting himself in a bathtub, but had succeeded only in badly damaging his brain. His belief in his own death began after that.

Another man logged into a psychology discussion board, and revealed, ” I believe that I have died and gone to the afterlife of which I’m uncertain whether I am in purgatory or hell. My surroundings and interactions with people vary so much that I sometimes think that I’m in hell.”

Cotard’s syndrome is broader, however, than the belief in one’s own death. The syndrome’s definitions seem to center around dramatic misperceptions of identity.

For example, in one case, a woman believed that she had been paralyzed, although she could, in fact, move.

The belief that one’s internal organs are missing, or are rotting away, is also frequently categorized as an aspect of Cotard’s syndrome. In an instance of this, a woman who was six months pregnant reported that she no longer had any stomach or heart, and her liver was rotting away.

In another case, a man in Iran believed that he had not only died, but had become a dog. Also in Iran, a woman who believed that she was nothing but a dead soul wandering in deserts and bathrooms cut off the tip of her nose and said that she had plans to do away with her wrinkles using an iron so that she could become a prostitute and make large amounts of money.

With symptoms so diverse, what makes Cotard Syndrome a single, coherent condition, rather than a diagnostic junk bucket?