Man in knitted sweater holding ginger cat.
February 23, 2017

Is there a connection between having cats and being crazy?

Due to the brain-damaging parasite Toxoplasma Gondii that they are known to host, cats have been cited as a potential cause of some mental disorders.

However, a new study published in the peer-reviewed journal Psychological Medicine has found no connection between cat ownership and psychotic behavior.

House cats are recognized as the principal host of T. gondii, which infects numerous warm-blooded animals, including humans. The infection causes the illness known as toxoplasmosis.

According to the Centers for Disease Control and Prevention, over 60 million people in the United States may have contracted the parasite. However, most people who acquire toxoplasmosis show few symptoms because their immune systems keep the parasite at bay.

However, in expectant mothers and those with depleted immune systems, the condition could cause severe health issues, including harm to the brain and eyes. Babies who are born to women infected with T. gondii during or just prior to their pregnancy are at the highest risk for developing acute toxoplasmosis. While toxoplasmosis can be acquired by eating undercooked meat, it is notably contracted via contact with animal feces containing the parasite.

Following Thousands of People

In the new study, researchers tracked almost 5000 people born in 1991 or 1992, who were followed until adulthood. The scientists had data on whether cats were living in the household while the mother was pregnant and/or raising the children.

"In our study, initial unadjusted analyses suggested a small link between cat ownership and psychotic symptoms at age 13, but this turned out to be due to other factors,” study author Francesca Solmi, a psychiatrist from the University College London, said in a statement. “Once we controlled for factors such as household over-crowding and socioeconomic status, the data showed that cats were not to blame. Previous studies reporting links between cat ownership and psychosis simply failed to adequately control for other possible explanations.

"The message for cat owners is clear: there is no evidence that cats pose a risk to children's mental health,” Solmi added.

The study’s conclusion is considerably more dependable than previous study in this area because the team followed families for nearly 20 years. This is more reliable than techniques used in previous research studies, which asked individuals with and without mental health issues to recollect details about their childhood. These kinds of accounts are more prone to recall errors, which can lead to dubious conclusions.

Previous research was also comparatively small and had noteworthy gaps in data, whereas the new study included a large population and was capable of accounting for missing information. The new study was not capable of evaluating T. Gondii exposure directly. However, the outcomes show that if the parasite does cause psychiatric difficulties then cat ownership does not appreciably boost exposure risk.

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