A new study has uncovered a puzzling connection between owning a cat and schizophrenia. Australian researchers reviewed 17 studies conducted over 44 years in 11 different countries. Their conclusion was startling: living with a feline could potentially double your risk of developing schizophrenic disorders. The findings raise fascinating questions about our bond with our four-legged companions and how it might affect the human mind.
In December 2023, a team of scientists from Australia published their groundbreaking analysis in the Schizophrenia Bulletin. Their research challenges how we think about domestic cats, suggesting a possible link between having one at home and a higher likelihood of developing schizophrenia-related symptoms. Though the discovery leaves much to explore, it sheds light on the environmental factors that could shape our mental health in ways we’ve never fully considered.
The Toxoplasma gondii parasite: an unexpected suspect
At the center of this mystery is Toxoplasma gondii, a microscopic parasite long associated with cats. For most people, it’s harmless — yet evidence now suggests it might have subtle but powerful effects on the brain.
• It can spread through undercooked meat, contaminated water, or contact with infected cats.
• Roughly 40 million Americans may carry the parasite, often without any symptoms.
• Once inside the body, it can travel to the central nervous system, altering how neurotransmitters behave.
Dr. John McGrath and his team at the Queensland Center for Mental Health Research reviewed studies dating back to 1995, when the cat-schizophrenia link was first proposed. Their results suggest people exposed to cats are about twice as likely to develop schizophrenia-related conditions.
Do you have a cat? This study on schizophrenia reveals the hidden side of purring and helps us understand the link between cats and mental disorders. © brightstars, iStock
A complex relationship between felines and mental health
While the Australian team found intriguing correlations, they’re quick to caution: correlation does not equal causation. The researchers noted that many studies varied widely in quality and consistency, and the critical age of exposure — perhaps between nine and twelve — remains uncertain.
An American study with 354 psychology students, for instance, found no direct connection between owning a cat and schizotypal traits. However, it did reveal that those who had been bitten by a cat scored higher on certain psychological measures — an observation that adds yet another twist to the story.
Beyond Toxoplasma: other possibilities
Although T. gondii remains the prime suspect, scientists aren’t ruling out other culprits. One possibility is Pasteurella multocida, a bacterium found in cat saliva, which may influence human behavior or emotional regulation in subtle ways.
Still, experts warn against jumping to conclusions or giving up your pet. The study’s authors urge caution and call for more rigorous, large-scale research. They recommend future studies that:
Involve diverse and representative populations.
Focus on understanding the biological mechanisms at play.
Examine additional environmental influences on mental health.
This line of research opens a fascinating new window into the interplay between humans, animals, and the mind. It reminds us that our daily surroundings — even our beloved pets — may hold clues to the intricate biology of mental illness. Far from causing alarm, these findings invite curiosity and deeper inquiry into the science of the brain and behavior.
