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According to a new Australian study, having a cat could double the risk of developing disorders linked to schizophrenia. The reason for this, however, is not yet clearly established.
Is there a link between having a cat at home and suffering from disorders linked to schizophrenia? Although causality has not yet been defined, the question has been raised since the 1990s, and the results of a new study would confirm this link among feline owners.
Australian researchers analyzed 17 other studies on the subject carried out over the last 44 years, from 11 countries, including the United States and the United Kingdom and also discovered “a significant positive association between cat ownership in the broad sense and an increased risk of schizophrenia-related disorders”.
“After adjusting for covariates, we found that individuals exposed to cats were approximately twice as likely to develop schizophrenia.”writes the team.
Several hypotheses put forward for decades
The idea that cat ownership may be linked to the risk of schizophrenia is not new. In a 1995 study, exposure to a parasite called Toxoplasma gondii was suggested as the cause. But so far, research has reached mixed conclusions.
T. Gondii is a generally harmless parasite that can be transmitted through undercooked meat or contaminated water. A bite from an infected cat or feces from an infected cat can also transmit T. Gondii. Once inside our bodies, T. Gondii can infiltrate the central nervous system and influence neurotransmitters. The parasite has previously been associated with personality changes, the emergence of psychotic symptoms and certain neurological disorders. However, there is no link to prove that T. Gondii caused these changes or that the parasite was transmitted to a human from a cat.
Some also associate exposure to cats with higher scores on scales measuring traits related to schizophrenia, which affects a person’s thoughts, feelings and behaviors, and psychosis-like experiences, but again , other studies do not show this link.
Other studies suggest that other pathogens such as Pasteurella multocida may be responsible.
A link to analyze further
If the study revealed here announces a doubling of the risks of schizophrenia among cat owners, it remains difficult to obtain solid proof of causal links. 15 of the 17 studies were case-control studies, the researchers themselves say. This type of research cannot prove cause and effect, and often does not examine elements that could have affected both the exposure and result. A certain number of studies examined were of poor quality, they also point out. Finally, the results from one study to another, on the importance of age for example (having a cat as a child or not) could be contradictory.
“In conclusion, our study confirms the existence of a link between owning a cat and disorders linked to schizophrenia”the authors still write, but more in-depth and better research is needed before definitive interpretations can be formulated.