You may have heard of Capgras syndrome, an eerie delusion that convinces people their loved ones have been replaced with nefarious clones. This is like that, only eerier: Due to what appeared to be a version of that syndrome, a 71-year-old man became “obsessed” with the idea that his cat had recently been replaced with an impostor cat, sent by the FBI to spy on him. The man’s ordeal was recently reported by the Discover blog Neuroskeptic, drawing from the case study in the journal Neurocase.
The Patient: This man, who is not named, had a history of heavy drinking and head injuries from his ice-hockey days; he had also been diagnosed with bipolar disorder. About six years before the cat-related delusion began, he stopped taking his anti-psychotics and soon became “acutely paranoid.” The case-report authors write that he would pass his wife “written notes stating that their house was being monitored, and often mistook persons in parking lots for Federal Bureau of Investigation agents.”
The Problem: The paranoia progressed from there. By the time he received medical treatment for his delusions, he had begun to believe his cat was in on the FBI plot against him. His physicians write:
He then became obsessed with the idea that his pet cat had been replaced by an imposter cat that was involved in the conspiracy against him. He knew that the current cat resembled his pet cat physically, but that the personality or psychic core of his cat had been replaced.
The Diagnosis: Again, this appeared to be an unusual case of an unusual disorder, Capgras syndrome. (Or, as his medical team phrased it in their write-up of his case, “Cat-gras” syndrome. Har-har.) Typically, Capgras patients believe their human loved ones have been replaced with evil look-alikes, but, as the case-report authors point out, this is not the first recorded case of a person becoming convinced their pet was an impostor:
Review of the literature reveals two cases reported in pet cats, two cases in pet birds, and one in a pet dog. The majority of these cases occurred during a psychotic episode with other paranoid and persecutory delusions, as in our patient.
It’s not clear what causes Capgras, but in this particular case, there are potentially some clues. The man showed signs of memory problems, too, which led his doctors to form a novel theory about what could be causing his delusions, as Brain Decoder reports:
Given this man’s problem with retrieving memories, his doctors propose another theory; that the delusions may result from a problem with linking an object (such as a cat) a person can see with his memories of this object. In other words, if you can’t properly retrieve your memories about a familiar object, you may think the object is new, but very similar to something you know, like a replica, or an impostor.
Weird that no one has so far proposed what seems like another perfectly viable theory: Perhaps this guy’s cat really was spying on him.