The life cycle of Toxoplasma gondii has two phases. The sexual part of the life cycle takes place only in members of the feline family, which makes these animals the parasite’s primary host. The asexual part of the life cycle can take place in any warm-blooded animal, like other mammals (including felines) and birds.
This latest study from the Stanley Medical Research Institute and Johns Hopkins University Medical Center suggests that since 1953 19 studies have shown the presence of Toxoplasma gondii antibodies in persons with schizophrenia and other severe psychiatric disorders. In many of the studies, the parasite was linked to psychological changes in humans when it was passed by a mother to her unborn child. However, two other studies have also linked exposure to cats in childhood as a risk factor for the development of schizophrenia.
Toxoplasma is associated with different, often opposite, behavioral changes in men and women, but both genders exhibit proneness to guilt (a form of neuroticism). Currently, some medications used to treat schizophrenia are also used to inhibit the role of Toxoplasma gondii in cell culture.