From cats to cortex: T. gondii and psychosis, depression, and anxiety

This review examines whether cat ownership, via exposure to the neurotropic parasite T. gondii, contributes to vulnerability for psychotic, depressive, and anxiety symptoms. T. gondii establishes lifelong latent infection in the brain and muscle, where it can modulate dopaminergic signaling, neuroinflammation, and tryptophan-kynurenine metabolism, providing a biologically plausible pathway to altered cognition, mood, and behavior. Epidemiological and meta-analytic data indicate small-to-moderate associations between T. gondii seropositivity and schizophrenia, with more variable but suggestive links to depression and anxiety. Evidence for cat ownership as an independent risk factor is inconsistent: some cohorts and recent meta-analyses report elevated odds of schizophrenia-related outcomes in those exposed to cats, whereas rigorously controlled studies frequently find attenuated or null effects. Methodological limitations, alternative explanations, and cultural implications are discussed, and priorities for mechanism-informed, longitudinal and interventional research are outlined.