Two delusional patients who believed that friends and relatives had died, despite them being around to prove otherwise, are described in an amazing 2005 journal article from the International Journal of Geriatric Psychiatry.
Although the Cotard delusion is well studied in psychiatry, where patients believe themselves to be dead, the report names the novel belief that another living person has died ‘Odysseus Syndrome’ – after the Greek legend where Penelope continued to believe that Odysseus had died, even after returning home from battle.
Both case studies are quite spectacular:
An 81-year-old lady presented to psychiatric services for the first time with sudden onset of ideas that her grandson had developed grossly swollen legs, inflammation of the brain, lethargy and extreme tiredness after infection by a fly which had picked up radioactive waste in the English Channel. Despite speaking to him over the telephone, she believed that he had died.
She believed that he had no stomach or internal organs, that his eyes had been removed and replaced with glass eyes, that his brain had died and been replaced by a clock and that he had expanded to become grossly obese. She described hallucinations of police providing commentary on his actions, but no other first rank symptoms of schizophrenia. Her mood was subjectively depressed but this clearly post-dated the onset of her delusions.
The lady in question had the beliefs for five years by the time of the report, although seemed to be getting on with life despite her mortality-related convictions.
The second case describes a lady with delusions that are reported as being similarly unshakeable.
A 73-year-old lady with a 40 year history of paranoid schizophrenia presented with grossly elated mood, over-activity, over-talkativeness, distractibility and grandiose beliefs. She sought help to prevent ‘experimentation’ on her lover’s health in the flat next door. She maintained he had developed ‘The Pox’ leading to his limbs rotting away, his heart being replaced by a machine and his brain requiring removal.
She believed nonetheless that he could send messages to her via television to which she could respond by arranging candles in a certain fashion. She was observed to be hallucinating to his voice. She maintained that he had died but come back to live in her mattress in a grossly distorted form, being very much larger than he had been in real life.
Link to DOI entry for journal article.
Link to PubMed entry for same.
Mind Hacks 
pretty scary stuff can your mind really do them things to you my dad had altzimers the last time i seen him befire he died he called me arny hes been dead about twenty 30 years before i was even born it was scary at the time but his own mind could not remeber me or my name even i must of looked a bit like him
This reminds me of how fragile our precious human life is, how easily one’s finely tuned balance can go off. Not to be paranoid, but our state of mind and our life are so impermanent, which reminds me to live as full and friendly a life as I can, in each moment.
This is some truly lovecraftian shit.
This actually sounds somewhat similar to the Capgras delusion, which VS Ramachandran argues is due to a disconnection between the prefrontal cortex and amygdala. This, he believes, results in the person with the delusion still capable of recognizing loved ones, with all the associated memories of them intact, yet there being no “emotional content” associated with them. This leads people to believe that their loved ones have been replaced by aliens, or impostors. Or, in this “Odysseus Syndrome”, being dead, perhaps?
It seems like an obvious connection to me, and I’m surprised the authors of that report don’t at least mention it.
This actually sounds like a really intense and somewhat fascinating way to go through life.