Infections et troubles bipolaires : l’exemple de la toxoplasmose

Abstract

The implication of infectious events in the development of major psychosis has recently gained increasing attention (see for review [2]). Rubella, herpes simplex virus (HSV), cytomegalovirus (CMV), Toxoplasma gondii (T. gondii), and other infections have been shown to be potent disrupters of fetal neurodevelopment leading to abnormalities of brain and behavior, including psychiatric disorders. In this context, the most studied link between a pathogen and psychiatric disorders concerns the association between T. gondii and schizophrenia [4]. T. gondii is an intracellular protozoan parasite which infects around one-third of the human population and resides encysted in the brain of immunocompetent hosts. However, the relationship between T. gondii infection and bipolar disorders is less documented due to paucity of information. The contextual link between toxoplasma infection and psychiatric disorders can be summarized as follows: (i) proven T. gondii's neurotropism and its impact on dopamine pathway [3], (ii) shared epidemiological characteristics between toxoplasma exposure and psychiatric disorders such as urban living, (iii) anti-parasite effect of antipsychotic drugs, (iv) parallel increase in T. gondii infection and incidence of psychosis in various populations [1], (v) a significantly high levels of antibodies to T. gondii in maternal sera whose offspring(s) subsequently develop psychiatric disorders later in life [5].