Exposure to Toxoplasma gondii<\/a>, a parasite associated with cats, has been suggested as one possible explanation.<\/p>\n But research so far has delivered mixed conclusions.<\/p>\n In their 2023 review and meta-analysis<\/a>, psychiatrist John McGrath and colleagues examined studies published over the last 44 years across 11 countries, including the US and the UK.<\/p>\n They found<\/a> “a significant positive association between broadly defined cat ownership and an increased risk of schizophrenia-related disorders.”<\/p>\n The exact causes of schizophrenia<\/a>, a brain disorder that affects how a person thinks, feels, and behaves, are varied and complex, and mostly unknown.<\/p>\n A combination<\/a> of genetic<\/a>, environmental<\/a>, and biological changes<\/a> in the brain<\/a> appear to play a part.<\/p>\n Studies have found<\/a> that being around cats during childhood might make a person more likely to develop schizophrenia; however, not all research<\/a> has found an association.<\/p>\n Some papers also link cat exposure to higher scores<\/a> on scales that measure traits related to schizophrenia and psychotic-like experiences.<\/p>\n But again, other studies don’t show this connection<\/a>.<\/p>\n McGrath and team wanted to get a clearer picture of whether cats and mental health may be connected.<\/p>\n “After adjusting for covariates, we found that individuals exposed to cats had approximately twice the odds of developing schizophrenia,” they write<\/a> in their published paper.<\/p>\n Among the 17 studies included in the review, one found<\/a> no significant association between owning a cat before age 13 and later developing schizophrenia.<\/p>\n But the same study did identify a significant link when narrowing down cat ownership to a specific period (ages 9 to 12).<\/p>\n This inconsistency suggests that the critical window for cat exposure is not well defined.<\/p>\n T. gondii is a parasite that can be passed to humans through an infected cat’s feces.<\/p>\n It can also be transmitted through undercooked meat or contaminated water.<\/p>\n The CDC estimates that T. gondii infects more than 40 million people in the US<\/a>, typically without any symptoms.<\/p>\n Researchers are still finding strange effects that infections may have<\/a>.<\/p>\n Once inside our bodies, T. gondii can persist in the central nervous system and may influence neurotransmitter systems.<\/p>\n The parasite has been linked to personality changes<\/a>, the emergence of psychotic symptoms, and some brain disorders, including schizophrenia<\/a>.<\/p>\n However, a link doesn’t prove that T. gondii causes these changes, or that the parasite was transmitted to a human from a cat.<\/p>\n Another study<\/a> included in the review, involving 354 psychology students in the US, found no association between cat ownership and schizotypy<\/a> scores.<\/p>\n However, those who had received a cat bite had higher scores than those who had not.<\/p>\n Other research<\/a>, which included people with and without mental disorders, discovered a connection between cat bites and higher scores on tests measuring particular psychological experiences.<\/p>\n The authors of that study suggested other pathogens, such as Pasteurella multocida<\/a>, may be responsible.<\/p>\n There are important limitations to keep in mind, including that 15 of the 17 papers reviewed were case-control studies.<\/p>\n This kind of research can’t show cause and effect, and it often doesn’t account for factors that may have affected both the exposure and the outcome.<\/p>\n The researchers also highlight the low quality of several of the studies examined.<\/p>\n Results were inconsistent across studies, but higher-quality studies suggested that associations in unadjusted models might be explained by other factors that could have influenced the results.<\/p>\n Related: A Brain Parasite Infecting Millions Is Far Less Sleepy Than We Thought<\/a><\/p>\n The authors say the field needs better-designed research that can more carefully account for confounding factors.<\/p>\n “Our review provides support for an association between cat ownership and schizophrenia-related disorders,” McGrath and colleagues conclude<\/a>.<\/p>\n “There is a need for more high-quality studies, based on large, representative samples, to better understand cat ownership as a candidate risk-modifying factor for mental disorders.”<\/p>\n![\"YouTube](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/06\/1780596792_919_0.jpg\")
frameborder=”0\u2033 allow=”accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share” referrerpolicy=”strict-origin-when-cross-origin” allowfullscreen><\/p>\n![\"Cat](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/06\/FuzzyGreyKittenLyingInKittyLitterBoxNextToHouseFurniture.jpg\")
Contact with infected cat feces is one possible route for T. gondii infection. (frosted_vulpes_ferrilata\/Unsplash<\/a>)<\/p>\n![\"Diagram](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2025\/11\/DiagramOfToxoplasmaLifeCycleFromCDC.gif\")
T. gondii is known to reproduce in cats (1), but can also be transmitted to humans through intermediate hosts (2, 5, 7). (CDC<\/a>)<\/p>\n![\"Subscribe](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/05\/FOMO-1200x628-_Dont-miss-the-next-breakthrough_-cosmic-colourful-642x336.jpg\")
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