Owning a Cat Does Not Cause Mental Illness, Study Finds

By Britni de la Cretaz 03/01/17

It’s time to put the stigma-filled “crazy cat person” stereotype to bed, once and for all.

Woman holding cat.

A new study has revealed that owning cats does not increase a person’s likelihood of developing mental illness.

"The message for cat owners is clear: there is no evidence that cats pose a risk to children's mental health," Dr. Francesca Solmi of University College London, who led the team of researchers, said in a statement.

The study was published in the journal Psychological Medicine. Researchers were attempting to examine a potential link between owning cats and the development of psychotic symptoms in early adolescence, around age 13. The study examined 5,000 people born in the early 1990s and followed them through their 18th birthday. They said this was a more effective way to study this question than asking people who were diagnosed with mental illness whether they had owned cats as children, according to NBC News.

The previously suggested link between cat ownership during a parent’s pregnancy and in childhood was suspected to be a result of the parasite Toxoplasma gondii which is found in cat feces and has been linked to schizophrenia. It can cause health problems during pregnancy and early childhood, and pregnant women are advised to avoid changing litter boxes for this reason. Some of those risks include birth defects and miscarriage.

It turns out that previous research that indicated a potential link between the parasite and mental illness had not been properly controlled for other factors. "Once we controlled for factors such as household overcrowding 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," Solmi said.

It is still unclear what causes schizophrenia, though family history of the illness is a factor. Other environmental factors have been identified as well, including things like substance abuse (which is often comorbid with schizophrenia) and migration—research has shown that the risk of schizophrenia is significantly increased among immigrants compared to native inhabitants of a location, as well as in their descendants. However, these correlations are not conclusive.

So while the etymology of the illness is still relatively unknown, cat ownership can now be crossed off the list. This is good news for the estimated 30%-37% of U.S. households and 17% of UK households that own cats.

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Britni de la Cretaz is a freelance writer, baseball enthusiast, and recovered alcoholic living in Boston. Follow her on Twitter at @britnidlc.