To the Issue of the Role Toxoplasma gondii in the Development of Schizophrenia

Literature data about possible mechanisms of interrelation of schizophrenia and toxoplasma infection were analyzed. High level of schizophrenia in family members of patients determines the role of genetic factors in its etiology. Numerous investigations determine the risk of schizophrenia development increases in 7-10 times in people who have the first stage of parentage with patient. Epidemiological examinations determined that toxoplasmosis can be placed in those regions or in some disease where there are not cat families. In regions where cat families occur rarely indices of distribution both toxoplasmosis and schizophrenia are low. Geographical regions with low middle level of antibodies to Toxoplasma gondii have low widespread of schizophrenia. Experimental examinations detected Toxoplasma gondii infectioning is able to retard and impair the memory and caused behavior changes in mice and rats. Examinations which determine that contaminated rats will become less careful that causes rat's life decrease and leads to Toxoplasma distribution. Results of examinations in genetics and neurobiology determine physiological and evolutionary mechanisms due which Toxoplasma gondii can multiple in brain and causes the change of behavior in mammals, achieving the theoretical basis for psycho-neurological diseases in person. Results of examinations on rats determine that Toxoplasma gondii causes behavior changes in infected rats, formation of numerous cysts of brain with numerous amygdala and nucleus accumbens predominance. By immunohistochemical methods numerous levels of dopamine in these cysts and also increase of dopamine by infected dopaminergic cells were revealed. Data of examination confirm that parasite can affect the metabolism of dopamine, determining the change of host's behavior. It is widely known dopamine metabolism and possibly glutamate plays an important role during schizophrenia. It should be noted that increased accumulation of dopamine and its discharge can be appeared at Toxoplasma infection and can Toxoplasma-induced schizophrenia. During the study of influence of Toxoplasma gondii on cognitive abilities in people who didn't have mental disorders in anamnesis it was determined that people with serological signs of Toxoplasma-infection have significantly smaller ability to memory. But some issues have not been studied. Some people have symptomless toxoplasma infection and mental disorders register only in small percentage from total number of contaminated ones. And also Toxoplasma gondii is only one possible factor which can affect the development of brain in womb or during the process of development of infants and cause late mental disorders in genetically predisposed people. Further investigations are actual and topical in order to develop new ways of treatment of schizophrenia and other mental disorders which can be associated with Toxoplasma infection.