This does not sound awesome.

A new study published in Journal of the Neurological Sciences has identified a link between Acyclovir - also known as the common cold sore cream Zovirax, (which can additionally be used to treat herpes, chicken pox and shingles) - and Cotard's syndrome, a rare condition causing people to believe they have died, that parts of their body do not exist, or that they have 'lost' their blood and internal organs.

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Examples of the syndrome have included a woman who used acyclovir as a treatment for shingles, then became overwhelmed by a strong feeling that she was dead. Even when symptoms lessened, she was adamant that her left arm did not belong to her. Another sufferer in 1990 believed that he was dead and was in hell, after being taken to a warm South Africa from colder Scotland, in an effort to help him recover.