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Research Gone Wild: Crazy Cats

Are those with pet cats more likely to develop schizophrenia?
(Photo: iStockPhoto)

(Photo: iStockPhoto)


In June, CBS News warned cat-lovers of a “little known danger lurking behind that furry little face”: the parasite Toxoplasma gondii. The article reported on two new studies: one that found people with schizophrenia were almost twice as likely to carry the parasite, and another showing schizophrenic adults were more likely to have had pet cats as kids.


Cats aren’t the host you should fear most. Most people pick up the parasite from gardening or eating undercooked meat, not from their pets, according to Arjen Sutterland, lead author on one of the studies. While cat bodies make the best T. gondii breeding ground, felines can shed the organism and transmit it to nearly any warm-blooded animal, including many that we eat. Further, the study linking pet cats to schizophrenia never tested the cats in question for T. gondii.


Your odds of developing schizophrenia are probably close to one percent, even with double the normal risk. And absent a rare genetic predisposition for the disorder, the parasite alone is not enough to cause a mental illness. “You have to be at risk already,” Sutterland says. So while the prevalence rate of T. gondii infection in humans is pretty high—around 25 percent worldwide, and as high as 55 percent in places like France that favor undercooked meat—the prevalence of schizophrenia is low. The link between T. gondii and mental illness is well established and warrants more study—but that doesn’t mean your cat is making you crazy.


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