Parasites in cat poop not linked to increased mental health problems — study

Previous studies claimed cat ownership could be related to the development of schizophrenia and other problematic mental health issues. A new study by University College London (UCL) researchers, however, finds no such link between the two.

The UCL researchers are the first to scrutinize how owning a cat during childhood—and the infection of a specific parasite found in house cats—is possibly linked to the development of psychosis.

According to the study’s lead author, research associate at University College London’s Division of Psychiatry Dr Francesca Solmi, few studies examining the link between the development of psychoses and cat ownership have been made. 

“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. Once we controlled for factors such as household over-crowding and socioeconomic status, the data showed that cats were not to blame,” she stated. “Previous studies reporting links between cat ownership and psychosis simply failed to adequately control for other possible explanations.”

In such studies, researchers queried participants—both with mental health disorders and otherwise—about what they remembered regarding their owning cats during childhood. Such methods can fall victim to recall inaccuracies, which in turn can contaminate any data gathered.

Solmi and her team’s research examined around 5,000 people hailing from the United Kingdom. The study followed these individuals, who were born in 1991 and 1992, until they were 18 years old. The study analyzed their birth information in order to find out if cats were present in their households during their mothers’ pregnancies, and during their childhood years. When the children were aged 13 and 18, they were taken to clinics to be assessed for symptoms of psychosis.

After taking potential factors that could confound the results into consideration, the study discovered that owning a cat during pregnancy and the childhood years was not involved in the development of psychotic symptoms in adolescence. 

The research did not directly measure exposure to the parasite. However, the data gathered suggests that if T. gondii causes mental health disorders, owning a cat plays no role in considerably increasing such an exposure.

Caution advised

Still, the researchers advised pregnant women to be extremely careful when handling cat litter.

“There is good evidence that T. gondii exposure during pregnancy can lead to serious birth defects and other health problems in children. As such, we recommend that pregnant women should continue to follow advice not to handle soiled cat litter in case it contains T. gondii,” explained University College London’s James Kirkbride, who served as the study’s senior author.

But there are other ways to contract T. gondii.

“You don’t have to own a cat to be exposed to contaminated feces,” offered Dr. E. Fuller Torrey, a Stanley Medical Institute associate director of research who has also studied toxoplasmosis and cat ownership. “For example, cats love sandboxes because of the loose soil.”

According to Fuller, neighborhood cats can contaminate loose soil with the parasite.

Solmi claims to be relieved that the study showed no link between owning a cat and the development of symptoms of psychosis. “Many people own cats, and it’s reassuring that our findings suggest that cat ownership is not associated with an increased risk of mental illness, as previously suggested," she said.

Solmi hopes other researchers can replicate the study in order to strengthen the evidence.

The study was published in the Psychological Medicine journal. — AT, GMA News