Infections and mental diseases: from tuberculosis to COVID-19.

COVID-19 pandemics reactivated interest in the relationship between mental diseases and infectious factors. In this narrative review, such association for tuberculosis, syphilis, toxoplasmosis, influenza, and COVID-19 was discussed. A connection between tuberculosis and melancholia was postulated for several centuries. In the 1950s, an anti-tuberculosis drug, iproniazid, was found to exert an antidepressant effect. In the 20th century, it was demonstrated that psychiatric disturbances connected with syphilis can be treated by an inoculation of malaria, which initiated immunotherapy. Increased frequency of Toxoplasma gondi infections in psychiatric illnesses was found and higher risk of the illnesses following the infection in pregnancy. A more frequent incidence of schizophrenia in persons born during the influenza pandemic in the second half of the 20th century was evidenced. Mental disturbances can result from an ancient infection of the human genome by retroviruses. Infection during pregnancy can increase their risk in later life. Pathogenic can be also an infection in adult life. COVID-19 causes significant early and late consequences for mental health. Two-year pandemics observation brought data on the therapeutic action of psychotropic drugs on SARS-CoV-2. Despite previous data on the antiviral action of lithium, a significant effect of this ion of the prevalence and course on the COVID-19 was not confirmed.