It has been suggested that infectious diseases transmitted early in life are a predisposing factor for the development of mental illness in the future. The purpose of a cohort study by C. Dalman et al. (Sweden), was to investigate whether viral or bacterial infections of the central nervous system (CNS), transmitted during childhood, increase the risk of developing schizophrenia or other non-affective psychoses and, if so, to identify the etiology of infections that led to similar consequences.

The study was carried out on a cohort of 1.2 million children born between 1973 and 1985. Data on hospitalizations for infections of the central nervous system between 0 and 12 years (2435 episodes of bacterial etiology and 6550 episodes of viral etiology) as well as the occurrence of non-affective psychoses of more than 14 years (2269 cases) were obtained from the Swedish state registers.

According to the results of the study, the risk of developing non-affective psychosis and schizophrenia was higher in people who had a viral CNS infection during childhood. For bacterial infections, no such dependence has been detected. In a subgroup analysis, it was shown that cytomegalovirus infection (16-fold increased risk) and mumps (3-fold increased risk) predispose to further development of mental illness.

Thus, serious viral infections transmitted in childhood can predispose to the onset of schizophrenia and other non-affective psychoses in the future. The presence of a relationship between the development of such complications and infections of a certain etiology has allowed the authors to suggest that the increased risk of developing mental illness is due to the pathogenicity of certain pathogens for brain parenchyma cells , including their ability to penetrate inside nerve cells, having a damaging effect on DNA. Confirmation of the relationship between infections of the central nervous system in childhood and the development of schizophrenia and other non-affective psychoses opens another way of preventing mental illness, researchers say.