This is a cross post. I feel obliged to try and make sure that cat owners understand the conclusions of a study referred to by many online newspapers. The study comes from Australia where arguably there is a strained relationship between domestic and feral cats and the population. Particularly feral cats which are denigrated and mercilessly slaughtered by the authorities on the continent to protect native species. I would gently suggest that there is a slight bias at least against the domestic cat in Australia which might have coloured the outcome of the study which DOES NOT PROVE a causal link between cats and schizophrenia in cat owners.
The point I am making is that when you read the study verbatim you come to a different conclusion than is stated or hinted/suggested by news media outlets of which there are many on the Internet.
For example, the Atlanta Journal-Constitution has a headline which states: “Study finds link between cats in schizophrenia is real”. That headline is unreal! 😒🤢
Study’s conclusion
It does not reflect the outcome of the study. I will quote the study which is called “Cat Ownership and Schizophrenia-Related Disorders and Psychotic-Like Experiences: A Systematic Review and Meta-Analysis”. Link to study: https://doi.org/10.1093/schbul/sbae027. A very technically-worded title but the outcome is pretty clear. Here it is:
Our findings provide support for the hypothesis that cat exposure is associated with an increased risk of broadly defined schizophrenia-related disorders; however, the findings related to PLE as an outcome are mixed. There is a need for more high-quality studies in this field.
John J McGrath and associates
The study looked at previous studies. Can we rely on previous studies? We don’t know. And they state that their findings provide a hypothesis that there might be a link between cat ownership and developing schizophrenia in the owner. A “hypothesis” is a proposal or suggestion but more information and further investigations are required in order to prove it. Clearly not a factual connection or a causal link.
They found “an association between broadly defined cat ownership and increased odds of developing schizophrenia-related disorders”. The word “association” does not prove a causal link. It just means that on their findings they saw more people with schizophrenia who were cat owners than in the general population. But that might mean that people who have developed schizophrenia somewhere else and for some other reason end up adopting a cat.
It does not mean that a cat caused schizophrenia in a person. This study is ultimately about the transmission of the Toxoplasma gondii oocysts from cats normally through their faeces to people. But a lot of people (and cats) contract toxoplasmosis through the food they eat such as eating raw or undercooked pork, beef, mutton or veal or drinking unpasteurised milk.
Alternative scenario
So, it is plausible to suggest that a person who suffers from schizophrenia or has psychotic-like symptoms might have developed that disease through drinking unpasteurised milk or eating raw food and then they adopt a cat.
That’s an entirely plausible situation which would be an alternative scenario to the one suggested by news media namely that domestic cats can give cat owners schizophrenia by transmitting the Toxoplasma gondii oocysts to their owner.
What news media should do
My conclusion is that news media must be more careful about reporting on studies. They should not simply repeat what other news media outlets have said. They should always return to the study and read it themselves. They should use the words of the scientists verbatim in order to be hundred percent clear as to what the study findings are. The language is important. The language used by news media outlets should not modify the language used by the scientists in their study conclusions. And there needs to be a general understanding of the underlying biological processes which in this case is the transmission of toxoplasmosis from cats the people through Toxoplasma gondii oocysts in faeces.
