Bad Science: Cats Do NOT Cause Schizophrenia


A report hits the news that cats cause an increased risk schizophrenia in people. According to this most recent study, published in Schizophrenia Research, , children exposed to cats at a young age are at higher risk of developing schizophrenia.

This study and others target a parasite Toxoplasma gondii as the culprit – which cats can carry.

These studies are pure nonsense –  if you read more, hopefully you’ll understand why. But first you need to better understand toxoplasma gondii

Even IF there’s is a link between a heightened risk of schizophrenia and the parasite  Toxoplasma gondii, cats are unlikely to be a primary culprit.

It’s true this parasite depends on the domestic cat to reproduce,  but Toxoplasma gondii does commonly occur in the environment. According to the Centers for Disease Control & Prevention, in the U.S. toxoplasmosis is more likely to be transmitted by gardening or preparing uncooked or contaminated meat, than from cats. When gardening there’s exposure to toxo from feral cats.

Cats just don’t get toxoplasmosis randomly. Cats get toxo from eating an infective rodent, or potentially from feces of another infectious cat.

Increasingly, Americans are keeping cats indoors only, dramatically reducing any odds of  pet cats being infected with toxoplasmosis. There are a wide range of estimates as to how many pet cats actually carry the parasite. Regardless, the odd of a cat carrying the pathogen who has never stepped outdoors is remote.

It’s also important to understand just how difficult it is to get toxoplasmosis from a cat that is even carrying the parasite in the first place.

You can NOT get toxoplasmosis from petting a cat, or getting kissed by a kitty. The only way to get toxo is via feces. And it not an easy disease to get.

That cat feces is only infectious about seven to ten days of the cats’ entire life, and what’s more the feces is only infectious if left in the litter box (or wherever the cat defecated) after a day and may take several days to become infectious.

In other words, if you scoop daily (within 24 hours), you are unlikely to become infected. if you scoop daily and then wash your hands with soap and water, it’s nearly impossible to be infected. And if you scoop daily, wear gloves when scooping and then wash your hands it’s about as close as you can come to impossible to be infected. It’s just is not going to happen.

Now back to that most recent study regarding childhood exposure to cats, and linking that with an increased chance to schizophrenia. The study blames toxoplasmosis as the culprit, not the cats themselves (though media reports often lose this fact).

How many young children have direct contact with a cat’s litter box? Sure periodically curious toddlers could land in the box, or put their fingers in – but direct contact with cats is not direct contact to toxoplasmosis. And I argue most toddlers really don’t get near that box, and if they do and the box has been scooped – there’s little chance of exposure. The study is seriously flawed.

Indeed, the toxo organism could potentially affect the brain in people, as it does in rodents, However, that’s never been demonstrated. So, the researchers here assume that cats have toxoplasmosis (which likely they may not) and that toxoplasmosis is actually causing the increased schizophrenia in these cat-owning homes.

Even if there is a slight increase in instances of schizophrenia when young children grow up with cats, Do we have any idea, it’s the cats that are responsible?

In others words – how do we know the cats have anything to do with this? The study never tested cats to determine if they are even carrying the parasite.

And if there was indeed exposure as toddlers to toxoplasmosis, statistically that exposure is actually less likely to come from pet cats than from toddlers playing outdoors in the garden or sandboxes, or even from meat not prepared properly.

I am a fan of good science, and moreover believe it is necessary to best understand our world. However, bad science only gives ‘haters’ a chance to rage online. In fact, there are many studies that suggest that growing up with cats is healthful in many ways – early exposure may lesson various allergies and also helps to teach children compassion and empathy, among many examples. Love your cats. Do scoop daily (for many reasons). And don’t worry. Cats do not cause schizophrenia.