T. gondii infections have the ability to change the behavior of rats and mice, making them drawn to, rather than fearful of, the scent of cats. This effect is advantageous to the parasite, which will be able to sexually reproduce if its host is eaten by a cat.[11] The infection is highly precise, as it does not affect a rat's other fears such as the fear of open spaces or of unfamiliar smelling food.
Studies have also shown behavioral changes in humans, including slower reaction times and a sixfold increased risk of traffic accidents among infected males,[12] as well as links to schizophrenia including hallucinations and reckless behavior. Recent epidemiologic studies by Stanley Medical Research Institute and Johns Hopkins University Medical Center indicate that infectious agents may contribute to some cases of schizophrenia.[13][14] A study of 191 young women in 1999 reported higher intelligence and guilt proneness in Toxoplasma-positive subjects.[15]
