Toxoplasmosis and schizophrenia

Toxoplasmosis is a disease caused by parasites present in mammals, birds and reptiles, which can be spread to people by contact with affected animals, especially cats, or by eating contaminated vegetables. It is an infection that does not generally involve complications except if it is contracted during pregnancy, since it can cause malformations in the fetus.

Now, a research team led by the University of Barcelona (UB) and the University of Granada (UGR), in Spain, has observed that people who have suffered from toxplasmosis and have different variants of a gene called COMT have a higher risk of suffer from schizophrenia.

The Pere Virgili Health Research Institute, the Rovira i Virgili University, the Villablanca Research Unit (UNIVDD) and the Mental Health Network Biomedical Research Center (CIBERSAM) have also participated in the research.

The research team, led by Paula Rovira and Blanca Gutiérrez, has verified that infection by toxoplasma Gondii, which causes toxoplasmosis, interacts with various modifications of the COMT gene and increases the risk of suffering from schizophrenia, especially with a variant called Met/Met . This is the first study to analyze the interaction between this specific genetic variant and the environmental infectious risk factor.

The COMT gene is responsible for metabolizing dopamine, one of the main neurotransmitters, and regulates its quantity in the brain. But variants like Met/Met are not as efficient in this process and cause an excess of dopamine. On the other hand, toxoplasmosis infection affects the speed of dopamine metabolism, so that in an infected person who also has this variant of the COMT gene, the chances of suffering schizophrenia due to this excess of dopamine are multiplied by 2.7. brain. Toxoplasmosis infection can cause psychotic symptoms in infected people, and can affect other neurotransmitters that play a secondary role in schizophrenia, such as serotonin and glutamate.

Human tissue severely infected by Toxoplasma gondii. (Photo: CDC/Dr. Edwin P. Ewing, Jr.)

Schizophrenia is a debilitating chronic psychiatric illness characterized by changes in perception, thinking, affect and behavior. Studies on the origin of this pathology point to the interaction of neurochemical, genetic and environmental risk factors, which would alter the dopamine neurotransmission system.

The study is titled “Toxoplasma gondii Seropositivity Interacts with Catechol-O-methyltransferase Val105/158Met Variation Increasing the Risk of Schizophrenia.” And it has been published in the academic journal Genes. (Source: URV)