Cat Parasite Linked to Schizophrenia in Owners

Cats became part of our lives over 7,000 years ago. Egyptians thought so highly of cats that one of their gods was depicted as one, and Egyptian “families actively mourned the deaths of beloved household felines.” In the Middle Ages, they became associated with witchcraft and slaughtered en masse – which appears to have had a major impact on the spread of the Black Plague across Europe. The rise of the middle class led to the increased domestication of the previously exclusively outdoor rodent wranglers, all according to the ASPCA. While the world may remain divided between “cat people” and “dog people” – there’s no mistake that felines have captured the hearts of many.

New research shows, however, that Toxoplasma gondii – a parasite commonly carried by cats – has been linked to mental illness in their owners, primarily schizophrenia. Cats are the only host in which the parasite, commonly referred to as T. gondii, is able to reproduce. The eggs laid by the parasite are expelled when the cat defecates, and can live for months in the proper climate according to popular science site IFLScience. If this parasite can make their way to a human host, it can cause toxoplasmosis, which can be acutely dangerous to pregnant women or those with weakened immune systems.

A recent study in Schizophrenia Research examines how childhood cat ownership impacts an individual’s likeliness of developing schizophrenia later in life. The study references two previous studies that “suggested that childhood cat ownership is a possible risk factor for later developing schizophrenia or other serious mental illness.” They attempted to replicate the findings using an extensive survey and were successful. It is important to note that this study does not definitively prove that T. gondii is responsible for causing mental illness in those surveyed, but there are other studies that do support the strong association.